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IC 


9054 



Bureau of Mines Information Circular/1985 



Technological Alternatives for the Conservation 
of Strategic and Critical Minerals— Cobalt, 
Chromium, Manganese, and Platinum-Group 
Metals: A Review 



By Russell J. Foster 



tftNT^ 




UNITED STATES DEPARTMENT OF THE INTERIOR 



75? 

*f/NES 75TH At*^ 



Information Circular 9054 



Technological Alternatives for the Conservation 
of Strategic and Critical Minerals— Cobalt, 
Chromium, Manganese, and Platinum-Group 
Metals: A Review 



By Russell J. Foster 




UNITED STATES DEPARTMENT OF THE INTERIOR 

Donald Paul Hodel, Secretary 

BUREAU OF MINES 
Robert C. Horton, Director 




As the Nation's principal conservation agency, the Department of the I 
has responsibility for most of our nationally owned public lands and natural 
resources. This includes fostering the wisest use of our land and water re- 
sources, protecting our fish and wildlife, preserving the environmental and 
cultural values of our national parks and historical places, and providing for 
the enjoyment of life through outdoor recreation. The Department assesses 
our energy and mineral resources and works to assure that their development is 
in the best interests of all our people. The Department also has a major re- 
sponsibility for American Indian reservation communities and for people who 
live in Island Territories under U.S. administration. 






Library of Congress Cataloging in Publication Data; 



Foster, Russell J 

Technological alternatives for the conservation of strategic and crit- 
ical mineral s— cobalt, chromium, manganese, and platinum-group metals. 

(Bureau of Mines information circular ; 9054) 

Bibliography: p. 50-53. 

Supt. of Docs, no.: I 28.27: 9054. 

1. Cobalt. 2. Chromium. 3. Manganese. 4. Platinum group. 5. 
Strategic materials— United States. 6. Mineral resources conservation- 
United States. I. United States. Bureau of Mines. II. Title. III. Se- 
ries: Information circular (United States. Bureau of Mines) ; 9054. 



TN295.U4 [TN799X6] 622s 



85-600141 



[333.8'516'0973] 



For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 



CONTENTS 

Page 



Abstract 

Introduction 

Background 

The importance of minerals 

Import dependency and vulnerability 

Supply-demand alternatives 

Substitution 

Processing 

Recycling 

Design 

Domestic supply 

Foreign supply 

Ocean minerals 

Stockpiles 

Perspectives 

Cobalt 

Background 

Uses and demand alternatives 

Superalloys 

Magnetic alloys 

Cemented carbides 

Wear-resistant alloys 

Steels 

Tool steels 

Maraging steels 

Catalysts 

Paint driers 

Other chemicals 

Pigments 

Ground-coat frit 

Glass decolorizers , 

Miscellaneous 

Supply alternatives 

Domestic 

Foreign 

Ocean minerals 

Stockpile 

Summary of demand and supply alternatives , 

Chromium 

Background 

Uses and demand alternatives , 

Metallurgical , 

Stainless steels 

Alloy steels 

High-strength low-alloy steels 

Tool steels 

Alloy cast irons 

Superalloys . 

Other alloys , 

Refractory — chromlte refractories 

Chemi cals 



1 


2 


2 


2 


3 


4 


4 


4 


5 


5 


5 


5 


6 


6 


6 


7 


7 


8 


8 


10 


11 


12 


12 


12 


13 


13 


14 


14 


14 


15 


15 


15 


15 


15 


16 


17 


17 


17 


18 


18 


20 


20 


22 


24 


25 


26 


26 


26 


27 


27 


28 



11 



CONTENTS — Continued 

Page 

Pigments and paints 28 

Leather tanning 29 

Metal finishing and treatment 29 

Drilling mud additives 29 

Water treatment compounds 29 

Wood treatment compounds 29 

Chemical manufacture and other uses 29 

Supply alternatives 30 

Domestic 30 

Foreign 30 

Stockpile 30 

Summary of demand and supply alternatives 31 

Manganese 32 

Background 32 

Uses and demand alternatives 34 

Metallurgical 34 

Iron and steel 34 

Nonferrous alloys 37 

Batteries. 37 

Chemicals and miscellaneous 38 

Supply alternatives 38 

Domestic. 38 

Foreign 39 

Ocean minerals 39 

Stockpile 39 

Summary of demand and supply alternatives 40 

Platinum-group metals 40 

Background 40 

Uses and demand alternatives 42 

Catalysts 42 

Automotive emission control 42 

Petroleum refining 43 

Chemical processing 44 

Electrical and electronic 44 

Contacts 44 

Thin- and thick-film circuits 45 

Thermocouples and furnace components 45 

Electrodes and miscellaneous 45 

Glass 45 

Jewelry 45 

Dental and medical. 46 

Miscellaneous 46 

Laboratory apparatus 46 

Crystal growth 46 

Supply alternatives 46 

Domestic 46 

Foreign 47 

Stockpile 47 

Summary of demand and supply alternatives 47 

Conclusions 48 

References 50 



ILLUSTRATION 



iii 



Page 



1. Flowsheet showing manganese inputs for production of steel by blast 

furnace-basic oxygen process 34 

TABLES 

1. U.S. consumption of cobalt, by end use 7 

2. World cobalt mine production, reserves, and U.S. imports 9 

3. Principal U.S. cobalt resources 16 

4. U.S. consumption of chroraite, by primary industry 18 

5. U.S. consumption of chromium ferroalloys and metal, by end use 19 

6. Domestic production and imports of chromium ferroalloys and chromite 20 

7. World chromite mine production, reserves, and U.S. imports 21 

3. Steel production in the United States, by type of furnace 28 

9. Consumption of manganese ore in the United States 32 

10. Consumption by end use of manganese ferroalloys and metal in the United 

States 33 

11. Domestic production and imports of manganese ferroalloys and manganese ore 34 

12. World manganese mine production, reserves, and U.S. imports 35 

13. Domestic manganese resources 38 

14. Platinum-group metals sold to consuming industries in the United States... 41 

15. Secondary platinum-group metals toll-refined in the United States 41 

16. World platinum-group metal production, reserves, and U.S. imports.. 43 

17. Total U.S. platinum resources 46 





UNIT OF MEASURE 


ABBREVIATIONS 


USED IN 


THIS 


REPORT 




°c 


degree Celsius 




mt 




metric ton 




°F 


degree Fahrenheit 




pet 




percent 




ft 


foot 




St 




short ton 




kW 


kilowatt 




tr oz 




troy ounce 




lb 


pound 




wt pet 




weight percent 




ra 
I 


meter 




yr 




year 





TECHNOLOGICAL ALTERNATIVES FOR THE CONSERVATION OF STRATEGIC 

AND CRITICAL MINERALS-COBALT, CHROMIUM, MANGANESE, 

AND PLATINUM-GROUP METALS: A REVIEW 

By Russell J. Foster ] 



ABSTRACT 



This Bureau of Mines review focuses on the extent to which technologi- 
cally and economically feasible programs in substitution, improved pro- 
cessing practices, including recycling, and design can achieve conser- 
vation of cobalt, chromium, manganese, and platinum-group metals, and 
thus reduce U.S. vulnerability to interruptions of supply. In addition, 
supply-side options — domestic and foreign resources, ocean minerals, and 
stockpiles — are identified. The report consolidates four major studies 
on these strategic and critical minerals sponsored entirely or partially 
by the Bureau in the last few years. These studies have been updated 
with further information from the recent literature. 



Physical scientist, Branch of Technical Analysis, Bureau of Mines, Washington, DC, 



INTRODUCTION 



Recently there has been an increase in 
public awareness of the importance of 
nonfuel minerals to the well-being of the 
United States. The specific issue of 
strategic and critical minerals avail- 
ability has generated much interest and 
controversy, as evidenced by the increas- 
ing volume of literature and the numer- 
ous conferences, workshops, and symposia 
convened on the subject. The Bureau of 
Mines, as part of its continuing role to 
identify and analyze problems and poli- 
cies regarding the Nation's mineral re- 
quirements, has been an active partici- 
pant in this area. 

Always included in any list of stra- 
tegic and critical minerals are cobalt, 
chromium, manganese, and platinum-group 
metals. The United States relies on 
imports for nearly all of its require- 
ments for these materials, and most of 
the principal sources of supply are re- 
mote and located in regions that have 
a relatively high risk, of political in- 
stability. Supply disruptions could ad- 
versely affect the manufacture of im- 
portant products for the economy and 
national defense. 

Cobalt is used in alloys for strength 
and heat and wear resistance, as a binder 
in cemented carbides, for magnetic and 
catalytic materials, and in paint driers. 
Chromium is used as an alloying element 
in stainless and alloy steels, as chro- 
mite refractories to line high-temper- 
ature furnaces, and to make chemicals for 
pigments, plating, and leather tanning. 
Manganese is important for its desulfu- 
rizing, deoxidizing, and alloying func- 
tions in iron and steelmaking; other uses 
of manganese are dry cell batteries and 
chemicals. The platinum-group metals ex- 
hibit several remarkable properties in- 
cluding resistance to high-temperature 



corrosion and oxidation, extensive cata- 
lytic activity, and high melting points, 
which enable them to be used as automo- 
tive, chemical process, and petroleum re- 
fining catalysts; in electrical and elec- 
tronic devices, dental materials, and 
jewelry; and for glass manufacturing. 

The utilization of technological alter- 
natives — substitution and conservation — 
presents a means of lessening the vul- 
nerability of the United States to 
interruptions of supply. 

Current essential U.S. cobalt needs are 
estimated at about 50 pet of present con- 
sumption. Existing technology is capable 
of achieving cobalt savings of over 10 
million lb annually by the next decade. 

Present U.S. chromium consumption could 
be reduced by approximately one-third by 
using available technology to substi- 
tute alternative materials and processes, 
to recover and recycle waste chromium, 
and to design for greater chromium 
efficiency. 

From a practical standpoint there is 
no substitute for manganese in steelmak- 
ing. However, the recent adoption of new 
steelmaking practices has been a major 
factor in substantially reducing the unit 
consumption of manganese per ton of raw 
steel produced. 

Platinum-group metals exhibit excellent 
recyclability . Automotive catalytic con- 
verters represent a considerable source 
of platinum-group metals, but the low 
concentration of the metals and the lo- 
gistics of converter collection are ob- 
stacles to recycling. 

Domestic deposits of these minerals 
would require market prices substantially 
in excess of those currently prevailing 
to warrant development. Bringing indi- 
vidual sites on-stream would generally 
require several years. 



BACKGROUND 



THE IMPORTANCE OF MINERALS 

The United States requires a continuous 
and substantial supply of minerals to 
sustain the domestic economy and maintain 
the national defense. In 1983 the crude 



nonfuel mineral production 2 of the United 
States was valued at $21.1 billion ($19.7 

^Production as measured by mine ship- 
ments, sales, or marketable production 
(including consumption by producers). 



billion in 1982, despite an economic re- 
cession) . These minerals were used as 
inputs for products which contributed 
over $200 billion to the U.S. gross na- 
tional product. Viewed in the context 
that a strong economy is essential to 
facilitate the development of defense 
materiel and to provide a defense mobili- 
zation base, it has been stated that 
"...adequate supplies of virtually every 
known material are a strategic necessity" 

U). 3 

In a narrower perspective, strategic 
and critical minerals are considered to 
be those for which National Defense 
Stockpile goals have been established. 
The Strategic and Critical Materials 
Stock Piling Revision Act of 1979 defines 
strategic and critical materials as those 
that (1) would be needed to supply the 
military, industrial, and essential ci- 
vilian needs of the United States during 
a national defense emergency and (2) are 
not found or produced in the United 
States in sufficient quantities to meet 
such needs. 

Even among the materials in the stock- 
pile there is a hierarchy with regard to 
their level of "criticality" ^2 - j>) . Some 
of the criteria usually considered in- 
clude the importance of the material to 
the economy (even a disruption cost that 
is small relative to the economy as a 
whole can still be substantial for a 
given industry or region); importance to 
the national defense (minerals that are 
essential to certain defense uses may not 
play a similar role in the context of 
overall economic activity); the attendant 
social and political (noneconoraic) ef- 
fects of a disruption; demand trends; 
domestic reserves and resources (cost of 
exploration, probability of discovery, 
availability); domestic capacity (mine, 
processing, fabricating); magnitude of 
import reliance; foreign supplier coun- 
tries (number, capacity, accessibility, 
ideology, political and economic stabil- 
ity); substitutability (present avail- 
ability, cost and time to develop); 
recyclability ; stockpiles (Government, 

■^Underlined numbers in parentheses re- 
fer to items in the list of references at 
the end of this report. 



industry). While basic materials such 
as iron, copper, and lead certainly are 
of importance to the Nation, others such 
as cobalt, chromium, manganese, and 
platinum-group metals assume more 
prominent positions from the perspective 
of possible supply problems. 

IMPORT DEPENDENCY AND 
VULNERABILITY (_5, 7-10) 

Since there is no uniformity in the 
qualitative and quantitative geologic 
distribution of the earth's mineral re- 
sources, no country is self-sufficient 
with regard to mineral requirements. The 
degree of import reliance varies consid- 
erably among the highly industrialized 
nations. The resource policy of the 
U.S.S.R., for example, has been charac- 
terized by a willingness to incur sub- 
stantial costs in order to promote a 
balanced development of all the materials 
required by an industrialized society; 
only when extremely high costs have been 
encountered has the Soviet Union been 
willing to accept some degree of reli- 
ance on foreign supplies (11). Japan, on 
the other hand, is basically a mineral- 
resource-poor country, heavily dependent 
upon raw material imports , and involved 
in many foreign mineral ventures. The 
United States has substantial mineral re- 
sources and has developed a large, multi- 
faceted minerals industry, but still re- 
lies in varying degrees on imports to 
supply a number of minerals, including 
several used in key sectors of the econ- 
omy and defense. Although some U.S. min- 
eral imports are necessitated by inherent 
resource limitations, others are based on 
economic advantage. As the Nation's im- 
port dependence becomes greater, however, 
in terms both of the number of minerals 
involved and the percentage of demand 
that is satisfied by imports, the pos- 
sibilities for supply difficulties in- 
crease. Minerals availability problems 
can result from periods of unusually 
strong demand, labor strikes, natural 
disasters, cartel actions, military con- 
flicts, politically motivated pressures, 
and internal strife. An additional fac- 
tor is the concept of a "resources war," 
which proposes that the Soviet Union, 



through its influence with certain 
mineral-producing nations or their adver- 
saries, may be in a position to selec- 
tively exert control over the flow of 
certain strategic and critical materi- 
als to the United States and its allies. 
Import dependency in itself is not nec- 
essarily a problem, but the position 
changes to one of vulnerability when the 
need for a material is such that a supply 
interruption would have severe economic 
and/or defense implications; the possi- 
bility of an interruption is enhanced by 
the actual or potential instability or 
unreliability of the supplier; domestic 
resources and foreign alternative supply 
sources are inadequate; and substitut- 
ability is limited. The oil embargo ini- 
tiated by Arab states in 1973 graphically 
demonstrated the significant impact that 
a supply shortage of a vital material can 
have. Likewise, the recent supply and 
price instabilities in the cobalt market 
showed that the availability of certain 
nonfuel minerals cannot be taken for 
granted. 

SUPPLY-DEMAND ALTERNATIVES (_5, 12-24) 

Despite the fact that achievement of 
self-sufficiency in minerals and materi- 
als is unlikely for the United States, 
steps can be taken to lessen import vul- 
nerability. These steps basically con- 
sist of reducing consumption through 
technological options and innovations in 
the areas of substitution 4 and conserva- 
tion (improved processing practices, re- 
cycling, and product design), and assur- 
ing the accessibility of primary supplies 
by developing alternative domestic and 
foreign mineral deposits and through 
stockpiling. 

4 Many analysts discuss substitution and 
conservation as separate entities, but 
strategic substitution can be considered 
as a form of conservation. Although sub- 
stitution may not reduce the overall use 
of materials, it can effectively reduce 
the requirements for a particular mate- 
rial by shifting the burden to one less 
critical. 



Substitution 

Substitution has both engineering and 
economic aspects — technical performance 
and cost effectiveness must be consid- 
ered. The time needed to develop a sub- 
stitute and to implement a successful 
substitution program can be considerable, 
particularly if new technology also is 
required. Under normal conditions, sub- 
stitution is a dynamic displacement pro- 
cess that occurs over time as a conse- 
quence of changing conditions such as the 
relative price of materials, technologi- 
cal advances, consumer preference, and 
Government regulation. 

Substitution is not a viable short-term 
solution to a sudden material shortage 
or price escalation unless the substi- 
tute possesses well-established proper- 
ties and performance comparable to the 
preferred material; requires only minimal 
changes in existing technology and pro- 
cessing and fabricating facilities; and 
is readily available at reasonable cost 
from domestic or accessible, reliable, 
foreign sources. Substitutes for strate- 
gic and critical materials rarely meet 
these criteria — the alternative material 
usually is less attractive both techno- 
logically and economically. Essential 
uses for a material are those that are 
not substitutable — such a material has a 
unique chemical or physical property, or 
functions on a scale or at a price that 
cannot be met by any other. 

Processing 

Losses of material occur at all stages 
of the materials cycle, from extraction 
of ore and conversion into intermediate 
forms, through fabrication of the fin- 
ished product, to eventual disposal or 
recycling. Significant losses occur in 
mining, milling, concentrating, and 
smelting, as fairly large amounts of ma- 
terial are discarded in mine and mill 
tailings and slag, but the cost of fur- 
ther incremental recovery is relatively 
high. Therefore, conservation efforts 
are most often directed at the materials 



fabrication stage. Of course, in the 
case of those strategic and critical min- 
erals where domestic production is non- 
existent, processing options are effec- 
tively limited to fabrication. 

Conservation is especially prominent in 
the metallurgical area, where the bene- 
fits of new processing technologies in- 
clude improving product yield with con- 
tinuous casting; minimizing alloying 
element loss through sophisticated melt- 
ing (vacuum induction melting, vacuum arc 
remelting, electroslag remelting) and re- 
fining (argon-oxygen decarburization, 
vacuum-oxygen decarburization) steps, and 
surface modification techniques (clad- 
ding, lining, coating, surface impregna- 
tion); reducing scrap in fabrication with 
near-net-shape technology (investment 
casting, powder metallurgy); and improv- 
ing quality control. 

Recycling 

Recycling offers an opportunity to pro- 
vide extended or alternative uses for a 
material. Effective recycling conserves 
not only the material itself, but in some 
cases energy as well, and can have the 
added benefit of improving environmental 
quality. However, the extent of recy- 
cling (i.e., home, prompt industrial, or 
obsolete scrap) depends upon relative 
primary metal prices, collection logis- 
tics, and available technology. Barriers 
in the form of laws, regulations, and 
policies also can place secondary mate- 
rials at a competitive disadvantage to 
their primary counterparts ( 17) . 

Design 

Design is a basic determinant of mate- 
rials use. Products and systems can be 
designed with an underlying conservation 
philosophy based on materials critical- 
ity, reliability, and recyclability , but 
under conventional circumstances where 
preferred materials are accessible the 
designer is concerned primarily with cost 
and performance considerations. 



Domestic Supply 

The development of domestic primary 
supply capability for strategic and cri- 
tical minerals offers a far more secure 
and accessible alternative to unreliable 
or potentially unstable foreign sources, 
but establishing domestic mineral produc- 
tion capacity may not be economically 
feasible and also can require a great 
deal of time. Regulations and restricted 
access to public lands can further deter 
domestic mineral production. Even if de- 
veloped, domestic deposits may be capable 
of satisfying only a modest share of con- 
sumption and/or may face rapid depletion. 
Nevertheless, established institutional 
means, in the form of the Defense Produc- 
tion Act, exist to provide subsidization 
of domestic mineral production. Title 
III of the act specifically authorizes 
the President to institute and maintain 
programs of financial assistance for the 
expansion of domestic production capacity 
and supply. 

Foreign Supply 

The reliability of foreign sources of 
supply is the crux of import dependency 
versus vulnerability. Obviously, risk 
can be minimized by diversifying supply 
sources among stable, friendly nations 
where possible. However, ensuring the 
development of an alternative foreign 
source of mineral supply and the contin- 
ued viability of the operation in a com- 
petitive world market may require direct 
financial or technical assistance, or a 
long-term, guaranteed purchase agreement 
on the part of the United States. 

In some instances, primary raw materi- 
als imports are being displaced by im- 
ports in the form of processed products, 
such as ferroalloys. There is a clear 
and accelerating trend for ore-producing 
countries to convert ore to higher valued 
intermediate products. This aspect of 
foreign supply has complex industrial and 
national security policy implications: 
Concentration of processed materials 



capacity outside the United States is 
leading to further import dependence and 
possibly vulnerability, and, by displac- 
ing domestic capacity, is contributing to 
the erosion of the Nation's industrial 
base. Furthermore, minerals in the Na- 
tional Defense Stockpile are of little 
utility without adequate processing capa- 
bility. Government options available in- 
clude domestic conversion of stockpiled 
ore to intermediate products; import tar- 
iffs or quotas; and maintenance of a min- 
imum level of capacity by directed pur- 
chasing or facility acquisition. 

Ocean Minerals 

Much of the interest in unconventional 
mineral resources — those that differ sig- 
nificantly from productive deposits in 
either mineralogy or geologic setting — 
centers on ocean minerals. Manganese 
nodules and crusts represent some of the 
world's largest untapped deposits of im- 
portant metals. Pacific Ocean nodules 
typically contain about 0.1 to 0.5 pet 
Co, 25 to 35 pet Mn, 1 to 1.5 pet Ni , and 
1 to 1.5 pet Cu on a dry basis (24); the 
nodules and crusts off the southeastern 
shoreline of the United States and south 
of Hawaii contain less manganese, but 
some are cobalt-rich. However, the po- 
tential of ocean mining is clouded with 
uncertainty. Although technically fea- 
sible extractive processes exist, the 
technology and logistics of mining and 
transport are complex and expensive. 
Under present market conditions, the 
economics of developing the mineral re- 
sources on the ocean floor are unfavor- 
able, and the unsettled international 
legal status of deposits outside the Ex- 
clusive Economic Zone (EEZ) presents a 
further complication. 

Stockpiles 

The availability of materials also can 
be increased by accumulating stockpiles 
to be held for release in times of short 
supply. The National Defense Stockpile, 
however, exists to supply military, es- 
sential civilian, and basic industrial 
needs of the United States during a na- 
tional defense emergency, and by law 



cannot be used for economic or budgetary 
purposes (24) . This greatly limits the 
accessibility of stockpile materials. 
Since 1939, there have been 28 releases 
from the stockpile, but only 4 have oc- 
curred during peacetime. Some stockpile 
materials lack immediate usefulness in 
terms of form if ore is held rather than 
processed materials without adequate 
domestic processing capability, and in 
terms of specifications if material ac- 
quired years ago has since been rendered 
obsolete by technological developments. 

Private industry stockpiling has been 
proposed as a reliable supplement to the 
National Defense Stockpile. Consuming 
companies are intimately acquainted with 
the materials used in their own manufac- 
turing processes, so they should be able 
to privately stockpile materials of opti- 
mum quantity, quality, and form for their 
use at any given time. However, when 
minerals availability is high and prices 
are low, concerns about stockpiling are 
minimal. Also, the cost of maintaining 
large inventories could be prohibitive 
for the private sector. 

PERSPECTIVES 

The issue of strategic and critical 
minerals availability has evoked a spec- 
trum of opinion regarding the likelihood 
and consequences of supply disruptions. 
The economy of the United States probably 
could adapt to most supply disruptions, 
but depending on the material involved, 
the time required for such adaptation 
could be lengthy, severe economic dis- 
locations might occur, and the noneco- 
nomic ramifications could be of equal or 
greater importance. 

The United States has historically been 
a net importer of several important min- 
erals, but it is improbable that major 
inroads into import dependence will be 
made by the private sector during times 
when minerals are readily available at 
low cost. The principal impediment to 
conservation is that there are few inher- 
ent incentives other than the economic 
factors of the market itself. Even mini- 
mal levels of resource exploration and 
substitution preparedness are expensive 
ventures with no assurance of eventual 



success or utility. However, "on-the- 
shelf" technology and existing stockpiles 
(provided that the form and specifica- 
tions of the stockpiled material are op- 
timally matched to needs) are the only 
short-term supply-demand solutions to a 
disruption. Other technological measures 
are ineffective if they are not under- 
taken until the onset of the problem. 

Therefore, it appears necessary to have 
continued foresight and awareness of pos- 
sible materials shortages, and plan con- 
tingency strategies so that otherwise 
manageable situations do not become cri- 
ses because of inadequate lead time. The 



characteristics and applications of the 
individual materials themselves will de- 
termine the optimum approach, but if 
these strategies involve conservation and 
substitution research and mineral explor- 
ation, the Government will have to make a 
commitment to an active role. 

Invariably included among the materials 
considered important to the Nation's in- 
dustry and defense, and most vulnerable 
to potential supply disruptions, are co- 
balt, chromium, manganese, and platinum- 
group metals. They are discussed indi- 
vidually in succeeding chapters. 



COBALT 



BACKGROUND 

Cobalt imparts strength and heat and 
wear resistance to certain alloys. It 
is also a strongly magnetic element and 
displays catalytic activity. As a re- 
sult, cobalt has a number of important 
uses including superalloys (gas turbine 
engines), wear-resistant alloys, tool 
steels, cemented carbides (tools, mining 



and drilling equipment), magnets, (rotat- 
ing machinery, indicating meters, tele- 
communications, loudspeakers), catalysts 
(petroleum, chemicals), and paint driers. 
The magnitude of domestic cobalt consump- 
tion by end use is shown in table 1. The 
cobalt resources of the United States 
cannot be considered reserves at cur- 
rent prices and with existing technol- 
ogy, and there has been no domestic mine 



TABLE 1. - U.S. consumption 1 of cobalt, by end use 
(Thousand pounds of contained cobalt) 



End use 


1981 


1982 


1983 






Quantity 


pet 


Quantity 


pet 


Quantity 


pet 




4,195 

1,687 

1,076 

488 

170 

176 

254 

1,279 

1,378 

329 

441 

40 

58 

109 


36 
14 

9 

4 

1 

2 

2 
11 
12 

3 

4 
.3 
.5 

1 


3,319 

1,544 

638 

446 

161 

165 

201 

789 

1,114 

382 

477 

32 

52 

148 


35 
16 

7 

5 

2 

2 

2 

8 
12 

4 

5 
.3 
.6 

2 


4,034 

1,711 

666 

472 

248 

54 

241 

1,064 

1,503 

366 

651 

41 

51 

217 


36 

15 

6 


Wear-resistant alloys (hardfacing) 


4 
2 




.5 




2 
9 




13 




3 




6 




.4 




.4 




2 




3 1 1,680 


100 


3 9,468 


100 


3 11,319 


100 


In _„J __ _.. ^.-_ 















Data may not add to totals shown because of independent rounding. 

Calculated apparent consumption, based on production, import and 
stockpile acquisitions, and stock changes, was 12.5 million lb in 1981, 
lb in 1982, and 15.7 million lb in 1983. 



export data, 
11.5 million 



production of cobalt since 1971. As a 
result the United States relies on 
imports for nearly all of its cobalt 
requirements — net import reliance has 
averaged over 90 pet for the past sev- 
eral years — and two of the principal 
sources of supply, Zaire and Zambia, are 
remote, developing countries in a region 
where political instability is a poten- 
tial risk. 

Calculated apparent consumption of co- 
balt in the United States was 15.7 mil- 
lion lb in 1983, far below the alltime 
high of 23.7 million lb in 1974. Never- 
theless, it represented a marked increase 
over the 1982 total of 11.5 million lb 
which was the lowest quantity consumed 
since 1961. The producer price stabil- 
ized at $12.50/lb during 1983, but the 
spot-market price was much lower, ranging 
from $4.75/lb to $6.40/lb. 

The cessation of stockpile sales of 
cobalt prior to 1977, and a subsequent 
period of rapidly increasing demand, 
eventually led Zaire to initiate an allo- 
cation program in May 1978. Shortly 
thereafter, a brief military invasion of 
Zaire's Shaba Province resulted in a tem- 
porary shutdown of cobalt operations. 
Although these events actually had mini- 
mal impact on cobalt production, con- 
sumers' concerns for the availability of 
cobalt sent producer and spot-market 
prices up dramatically, to $25/ lb and 
over $40/lb respectively. Subsequent 
conservation efforts coincided with an 
economic downturn to significantly reduce 
cobalt demand, and, beginning in 1981, 
prices responded accordingly. Despite 
the recent trend of declining consump- 
tion, U.S. demand for cobalt is forecast 
to increase at an annual rate of 2.7 pet 
from 1981 to the year 2000. The world 
production of primary cobalt, world co- 
balt reserves, and exports to the United 
States are listed in table 2. 

USES AND DEI4AND ALTERNATIVES 

Superalloys (24-26) 

Cobalt is used in many superalloys to 
enhance their high-temperature properties 
and processability. With respect to co- 
balt, superalloys can be classified as 



cobalt-base (40 pet or more Co) and 
cobalt-bearing, nickel-base (8 to 20 pet 
Co). The major use of superalloys is in 
gas turbines, principally for jet air- 
craft engines, and to a lesser extent for 
other propulsion systems, power genera- 
tion, and gas compression. Much of the 
alloy substitution that could readily 
take place occurred during the 1978-80 
period. Limited laboratory results from 
NASA's Conservation of Strategic Aero- 
space Materials (COSAM) program, which 
has the objective of minimizing the stra- 
tegic metal content of vital aerospace 
components ( 27 ) , have shown that current 
U.S. superalloys may contain about 50 pet 
more cobalt than is necessary for most 
applications, but the potential for using 
further substitutes for cobalt in super- 
alloys is limited in the short term, es- 
pecially for aircraft applications, be- 
cause of the stringent standards, high 
costs, and long lead times required to 
certify substitute alloys. The current 
engineering of superalloys is dictated 
more by the need to meet stringent prop- 
erty and reliability specifications than 
by economic or conservation considera- 
tions. With only 200 to 900 lb of cobalt 
required for a multimillion-dollar jet 
engine, materials costs will not drive 
the designer toward an alternate selec- 
tion unless a parallel alloy and process 
that can be readily put to use have been 
established. Otherwise, only a major 
systems benefit can provide sufficient 
incentive for change. A ceramic gas tur- 
bine engine can operate at higher temper- 
atures and therefore greater thermal ef- 
ficiency than its metallic counterpart 
(28). Ceramics also provide improved 
corrosion resistance and lower density. 
However, because of their brittleness, 
ceramics as yet do not offer the dura- 
bility and reliability required for long- 
term applications, such as aircraft 
engines. 

Many superalloys are used with protec- 
tive coatings, some of which are them- 
selves cobalt-rich. The possibility of 
using other metallic coatings in place of 
cobalt depends on the particular applica- 
tion for which the coating is intended. 
For high-temperature oxidation (oxygen 
environment) cobalt could be replaced by 



TABLE 2. - World cobalt mine production, reserves, and U.S. imports 
(Thousand pounds of contained cobalt) 



Country 



Mine output 



1981 



1982 f 



1983 e 



Reserves 



U.S. imports 



1981 



1982 



1983 



Australia 

Belgium-Luxembourg 

Botswana 

Brazil 

Canada 

Cuba 

Finland 

France 

Germany, Federal 

Republic of 

Greece 

India 

Indonesia 

Japan 

Morocco 

Netherlands 

New Caledonia 

Norway 

Philippines 

South Africa, Republic of 

U.S.S.R 

United Kingdom 

Yugoslavia 

Zaire 

Zambia 

Zimbabwe 

Other 

Total 



3,672 



560 

NA 

4,586 

3,780 

2,280 









1,740 



814 



2,198 


4,800 





34,000 

7,530 

220 





3,990 



560 

NA 

3,096 

3,300 

2,050 









1,540 



598 



1,258 


5,000 





24,920 

7,160 

220 





4,000 



560 

260 

3,492 

3,640 

2,000 










600 


1,320 


5,200 





24,920 

7,060 

140 





50,000 



20,000 

NA 

100,000 

400,000 

50,000 





30,000 

40,000 

400,000 







500,000 



300,000 

40,000 

300,000 



20,000 

3,000,000 

800,000 

5,000 

NA 



83 

939 

633 



1,846 



1,206 

367 

213 







1,624 



64 

87 

1,631 



464 



599 



4,176 

1,513 



149 



66,180 



53,692 



53,192 



6,000,000 



15,594 



169 
613 
364 


1,483 


798 
336 

255 







1,024 



28 



852 



266 



271 



4,971 

1,164 



276 



12,870 



168 

1,123 

400 



1,950 



1,017 

91 

79 







462 



507 



707 



185 



367 



7,723 

2,347 

32 

64 



17,221 



e Estimated. Preliminary . NA Not available, 



'Rounded. 



iron or nickel with little or no loss in 
usable life. In a high-temperature, sul- 
fidic corrosion environment, replacement 
of cobalt would definitely decrease coat- 
ing service life. Although cobalt-base 
coatings are used in low-temperature cor- 
rosive environments, cobalt may not be 
necessary. Ceramic thermal barrier coat- 
ings may permit cobalt to be replaced in 
some environments provided repeated ther- 
mal cycles can be tolerated. The effect 
on coatability of decreased cobalt in the 
substrate alloy also must be considered, 
but the presence or absence of cobalt in 
alloy substrates or coatings does not ap- 
pear to have much bearing on the process- 
ability of coatings using advanced coat- 
ing techniques. 

The superalloy industry generates a 
high proportion of scrap and waste 



because of the large number of different 
and complex alloys produced and the use 
of composites. Efforts directed at re- 
ducing the amount of scrap have taken 
the form of a continuing trend to pro- 
duction of "near-net-shape" components — 
substitution of investment castings for 
forgings and the recent development of 
powder processing. In addition, modern 
melting and analytical methods have sig- 
nificantly reduced off-spec heats; vacuum 
or controlled atmosphere teeming greatly 
reduces ingot defects; care is taken to 
minimize the quantity of material removed 
with end crops, edge trimming, and fin- 
ish conditioning. These are evolutionary 
changes already well under way that may 
reduce the actual quantity of in-house 
scrap produced by 25 pet. The best 
opportunity for significant further 



10 



reduction in scrap is the adoption of 
near-net-shape processing for a wider 
variety of shapes and components. Scrap 
recycling is an established practice in 
the superalloy industry. The materials 
recycled are solid metallic scrap from 
primary production sources — the predomi- 
nantly clean, well identified solids and 
processed turnings which are relatively 
easy to collect, handle, verify (compo- 
sition), and melt. However, approximate- 
ly 40 pet of wrought superalloy scrap and 
50 pet of cast superalloy scrap is not 
directly recycled domestically for pro- 
duction of these alloys. It is down- 
graded for use in the steel industry, 
lost, or exported. Dusts, grindings , 
furnace scale, and pickle sludges are 
often mixtures of every alloy produced in 
the plant and hence are low grade, finely 
divided, and costly to dry, with inher- 
ently limited use for recycling. Obso- 
lete scrap solids are not efficiently 
recycled — turbine components may become 
contaminated in service with elements 
such as lead and sulfur that are highly 
detrimental to superalloy properties; 
separation of superalloy components that 
have been fabricated into more complex 
assemblies by welding, brazing, or coat- 
ing can be difficult; the collection 
of obsolete scrap on a small scale pre- 
sents logistical difficulties. The best 
prospect for improving cobalt recovery 
for use in superalloys is improving the 
efficiency of recovering obsolete solid 
scrap, and it is likely that a greater 
proportion of obsolete scrap solids will 
be directly recycled in the future. How- 
ever, a significant amount will continue 
to be downgraded — a number of processes 
for separating individual elements from 
complex superalloy scrap have the ability 
to recover some or all elements in a pur- 
ity suitable for use in superalloys, but 
commercial-scale plants are marginally 
economic. 

Magnetic Alloys (24-26) 

Cobalt is the strongest magnetic ele- 
ment. It increases the saturation mag- 
netization of iron and has the high- 
est Curie temperature known. Therefore, 



permanent magnets made with cobalt are 
generally superior. The principal magnet 
applications are rotating machinery, in- 
dicating meters, telecommunications, and 
loudspeakers. The largest use of cobalt 
in magnetic devices is in Alnico perma- 
nent magnets (alloys of iron, nickel, 
cobalt, aluminum, and lesser amounts of 
other elements) . Together with iron- 
chromium-cobalt deformable magnets they 
total about 90 pet of cobalt used in mag- 
netic applications. Iron-chromium-cobalt 
alloys offer magnetic characteristics 
nearly identical to Alnico but at much 
lower cobalt content. These types have 
a magnetic energy density 3 to 4 times 
greater than that of Alnico with only 
double the cobalt content and are well 
suited for small, high-torque, fast- 
response, electric motors. Soft cobalt- 
containing magnetic materials (e.g. , 2V 
Permendur, Supermendur) find minor use 
in aircraft generators and telephone re- 
ceiver diaphragms; semihard cobalt-con- 
taining magnetic materials (e.g., Remen- 
dur, Nibcolloy) find minor use in reed 
switches, memory applications, and hys- 
teresis motors. 

A number of parameters must be consid- 
ered when magnetic materials are speci- 
fied for any given application — magnetic 
strength, size, operating conditions, and 
cost. Yet, the magnetics industry has 
reduced its dependence on cobalt through 
the use of low- or no-cobalt substitutes 
more than any other industry. 

Hard ferrites (ceramic magnets) have 
virtually replaced Alnicos in all large 
loudspeakers. For smaller speakers iron- 
chromium-cobalt magnets are feasible, and 
for the smallest speakers rare earth- 
cobalt magnets have merit, but further 
substitution is unlikely at current co- 
balt prices. Modest substitution could 
occur at 3 times current prices, but even 
at 10 to 20 times current prices about 10 
to 20 pet of the loudspeakers would still 
require cobalt. 

Rotating machinery utilizes primarily 
permanent magnet generators, motors, and 
magnetos. Hard ferrites are widely used 
up to 10 kW power because of cost 
effectiveness. Greater than 10 kW pow- 
er demands high-energy-density magnets, 



11 



particularly rare earth-cobalt. At a 
tenfold cobalt price increase strenuous 
efforts would be made to use cobalt-free, 
or cobalt-efficient, materials, or possi- 
bly revert to electromagnetic designs, 
although about 10 to 20 pet of the market 
could justify cobalt. 

The designs of certain instruments and 
indicating meters are closely tied to 
specific materials. Only at 10 times the 
present cobalt price would the use of 
more cobalt-efficient materials occur, 
and the development of new meter designs 
operating on different principles be 
considered. 

In the field of telecommunications the 
potential for less cobalt use is sub- 
stantial. Technological changes such as 
miniaturization, large-scale integration, 
digital signaling, and photonics will 
greatly reduce cobalt requirements. 

The magnetic industry makes effective 
use of home or runaround scrap generated 
during magnet manufacture, but there is 
little recycling of obsolete scrap except 
large magnets in scrapped equipment and 
magnets in leased equipment such as tele- 
phones. Public utilities could do the 
same with damping magnets in watt-hour 
meters , but cobalt prices would have 
to increase at least threefold. The pri- 
mary barriers to recycling are identifi- 
cation and collection of obsolete scrap 
from widely dispersed locations and the 
cost of removing small components from 
scrapped units. 

Cemented Carbides (24-25) 

Cobalt is used as the binder in the 
structure of cemented tungsten carbides 
in amounts ranging from 3 to 25 pet. 
These alloys are characterized by excep- 
tional combinations of hardness, tempera- 
ture and abrasion resistance, high elas- 
tic modulus, strength, and toughness, and 
are widely used in tools for machining 
cast iron and nonferrous metals, metal 
forming, raining, oil and gas well drill- 
ing, and a variety of highly stressed 
structural applications. In machining 
ferrous metals, additions of titanium 
carbide, tantalum carbide, and colura- 
bium carbide are employed to improve the 



cutting tool's resistance to chip erosion 
("cratering") and to the effect of high 
cutting-edge temperatures generated dur- 
ing the machining operation. 

Substitution of other binder metals and 
alloys in cemented carbides has received 
the concentrated attention of researchers 
over the past 60 yr. In certain cemented 
carbide alloys designed to combat com- 
bined corrosion and abrasion, nickel 
and iron have shown the most promise as 
substitutes with chromium additions to 
impart corrosion resistance. Titanium 
carbide-base cemented carbides commonly 
containing nickel as the binding metal 
have found an important but small and 
specialized field of use. The same is 
true of aluminum oxide-base ceramics and 
titanium carbide-aluminum oxide "cer- 
mets." Other materials receiving atten- 
tion for specialized uses include silicon 
nitride as a base compound for cutting 
tool materials and polycrystalline dia- 
mond and cubic boron nitride cutting 
tools for specialized areas of metal and 
composite material cutting. However, 
these are not capable of mass replacement 
of cobalt-bearing cemented carbides with- 
out an unacceptable loss of productivity 
and economy in metal cutting because of 
their brittleness and low cutting-edge 
strength. Coal and hard-rock mining and 
oil and gas well drilling applications 
depend on the unique combination of prop- 
erties possessed by tungsten carbide- 
cobalt alloys. Cobalt remains the supe- 
rior binder, and there are no apparent 
practical alternatives available or in 
sight today. The same is true for cer- 
tain metal-forming and superpressure ap- 
plications. Research on replacements for 
cobalt as a binding metal is primarily 
motivated by the desire to improve prop- 
erties (corrosion resistance) of current- 
ly available alloys, and to reduce risks 
associated with dust exposure. 

Virtually all cemented carbide manufac- 
turing scrap is recycled. However, obso- 
lete scrap recycling is less extensive 
because of the wide dispersion of carbide 
users. Nevertheless, direct recycling of 
obsolete cemented carbide scrap has be- 
come established with several process 
routes available. The current practical 



12 



limit of cemented carbide scrap that is 
recycled ranges from 15 to 80 pet depend- 
ing on the application. Although theo- 
retical maxima can reach 65 to 95 pet, 
the probable practical limit is estimated 
at 40 to 85 pet. 

Wear-Resistant Alloys (24-26) 

The composition of the most commonly 
used wear-resistant (hardfacing) alloys 
is 50 to 70 wt pet Co for application in 
automotive engine valves, fluid valves, 
knives, cutters, erosion shields, hot- 
working dies, and bearing surfaces that 
cannot be lubricated. The mode of wear — 
abrasive, adhesive, or erosion — deter- 
mines the criticality of cobalt use. 
Cobalt offers important performance bene- 
fits against galling and cavitation ero- 
sion wear, but alloys with lower cobalt 
levels provide alternatives. For erosion 
from particle impingement there also ex- 
ist opportunities for alternative alloys 
with lower or no cobalt. Nickel-base al- 
loys are gaining in hardfacing of automo- 
tive engine valves and valve-seat in- 
serts. The nickel-base properties are 
comparable or better, are lower cost, and 
are more easily processed as powder. 
However, at current cobalt prices there 
is little incentive to replace high- 
cobalt wear-resistant alloys with alter- 
natives. In addition, the performance 
of cobalt alloys is well established. 
Should cobalt prices increase, so would 
the incentive for substitution. At 10 to 
15 times current prices, efforts to use 
substitutes would sweep all areas of wear 
application, and up to half the cobalt 
currently used could be conserved. 

Hardfacing and coating alloys are often 
utilized as powder metallurgy products 
deposited as plasma or flame-sprayed pow- 
ders. The system typically does not re- 
cycle the overspray, the scrap, or hard- 
facing or coating material from obsolete 
parts. Hardfacing rod made by continuous 
casting and typically used in valve seats 
and components for diesel engines is not 
recycled once the seats are taken out of 
service because of high iron contamina- 
tion, since the alloy is hardfaced onto 
an iron substrate. 



Steels 
Tool Steels (24-26, 28 ) 

Tool steels are metallurgically com- 
plex with six or more major alloying ele- 
ments and a large number of commercially 
recognized compositions. Raw materials 
represent a fraction of overall produc- 
tion costs because of the special pro- 
cessing involved, so improved performance 
can often justify the use of high-cast 
materials. The heat generated in the 
machining of some materials (stainless 
steels, superalloys, titanium alloys), 
can soften the tool steel so that per- 
formance deteriorates. Cobalt is added 
(5 to 12 pet) to high-speed tool steels 
to increase attainable hardness and im- 
prove hot hardness and hardness reten- 
tion, thus improving tool life. Except 
for high-speed tool steels the only 
cobalt-bearing standard grades of tool 
steels are hot-work and cold-work tool 
steels, and the amount of cobalt in them 
is minor compared to the high-speed tool 
steels. Comparable cobalt-free high- 
speed steels have been developed, so the 
presence of cobalt is not essential, and 
its use can be determined by economic 
considerations. The development of coat- 
ings (titanium carbide, titanium nitride) 
that increase tool life also will mini- 
mize the need for cobalt-bearing steels. 

Opportunities for reduction of scrap 
generated during conventional processing 
are limited. New processing methods, 
such as electroslag remelting, have pro- 
vided better product yield and hence less 
scrap. Further improvement in yield can 
be expected from the adoption of semicon- 
tinuous casting of intermediate-size bil- 
lets, or powder metallurgy, but neither 
process comes close to entirely eliminat- 
ing scrap. Although a substantial por- 
tion of tool steel scrap is recycled, the 
efficiency of recovery of the alloying 
elements is significantly lower than with 
superalloys. Almost all solid in-house 
scrap and prompt industrial scrap solids 
are separated by grade and recycled (re- 
melted). Some obsolete scrap, primar- 
ily large monolithic industrial cutting 
tools, is also recycled. Particulate 



13 



scrap such as furnace dust and mill scale 
is generally collected with other tool 
steel and alloy steel wastes produced by 
the mill, but oily grindings produced by 
tool fabricators are not recycled because 
of their high residual phosphorus con- 
tent, which is unacceptable to tool steel 
manufacturers. Theoretically all tool 
steel scrap could be carefully identified 
during collection and recycled directly 
or after further processing. However, 
the fact that it is so often mixed with 
much lower grade scrap makes more effi- 
cient collection impractical. Improved 
sorting and identification techniques 
have made it possible to recover virtual- 
ly all solid scrap for recycling directly 
within the mill. Research aimed at de- 
vising methods of treating tool steel 
grindings to make them suitable for recy- 
cling is underway. Procedures for recov- 
ering mixed alloy sludges generated by 
electrical discharge machining processes 
are also likely to be developed in the 
next few years. Some work has been done 
on the chemical separation of the ele- 
ments in tool steel scrap, but this may 
be too costly except in times of severe 
shortage, and there would be a 3-yr lead- 
time factor. 

Maraging Steels (24) 

Maraging steels (predominantly nickel, 
cobalt (7.5 to 12 pet), molybdenum, and 
titanium) had initial applications in 
ultra-high-strength materials with good 
toughness for use in the aerospace in- 
dustry, but are now used for tools and 
other structural applications as well. A 
cobalt-free alloy containing more tita- 
nium than the original alloy was recently 
developed and shows properties consistent 
with those of the cobalt-bearing grade. 
Therefore, cobalt is not essential, but 
for aerospace applications, time-con- 
suming and costly qualification testing 
would be required before substitution 
could be made. 

Catalysts (24) 

The catalytic activity of cobalt is 
utilized in several chemical and 



petroleum refining processes. Hydro- 
treating processes utilize 8 to 11 wt pet 
molybdenum and 1.5 to 3.5 wt pet cobalt 
(or molybdenum and nickel) on an alumina 
support to remove sulfur, nitrogen, and 
metals (typically vanadium and nickel) 
from various petroleum streams. As the 
fundamentals of catalysis are better un- 
derstood, and the quantifiable physical 
and chemical characteristics can be bet- 
ter correlated with measures of perform- 
ance, the same results will be obtainable 
with lower metals content. Molybdenum- 
nickel catalysts are widely used in a 
variety of hydrotreating processes and 
are more effective than molybdenum-cobalt 
catalysts for denitrif ication and hydro- 
gen uptake, whereas molybdenum-cobalt 
shows higher desulf urization activity. A 
significant portion of molybdenum-cobalt 
catalytic applications could use nickel 
without any substantial process penalty. 
So far, reclaimers have taken out only 
molybdenum and vanadium from spent cata- 
lysts, but plants with the capability to 
recover essentially all the cobalt from 
any type of catalyst are envisioned. Re- 
fineries also are gradually increasing 
the practice of catalyst regeneration — 
cleaning up spent catalyst and returning 
it to useful life. 

Hydrof ormylation reactions produce C 4 
to C13 alcohols. C4 to C5 alcohols are 
used as solvents; the higher alcohols are 
further processed to produce plasticiz- 
ers; some C j 2 alcohol is used to make 
detergents. The oxo process reacts ethy- 
lene or propylene with carbon monoxide 
and hydrogen over a cobalt catalyst (as 
a soluble salt) to form these linear 
alcohols. These alcohols are also avail- 
able from the same process using a rho- 
dium catalyst, as well as via an alter- 
nate route (Ziegler-type oligomerization) 
which uses catalysts other than cobalt. 
Oxo alcohol catalysts are recycled, bu«_ 
eventually buildup occurs on the process 
equipment, requiring that the material be 
reclaimed. About 90 pet of the cobalt is 
now being reclaimed, and the remainder is 
lost in handling. 

Terephthalic acid and dimethyltereph- 
thalate are produced from paraxylene for 
use in the production of polyester fibers 



14 



and films. The oxidation steps in the 
reaction are promoted by a cobalt-manga- 
nese catalyst. There does not appear to 
be a substitution alternative to cobalt 
in this process. There is recycling of 
the catalyst, but as byproducts build up, 
the catalyst is withdrawn and cobalt- 
containing sludge is incinerated and sent 
out for reclamation of cobalt. As a ma- 
jor user installs incineration facili- 
ties, the amount being reclaimed will 
increase to 90 pet. 

Pyrolysis gasoline is the byproduct of 
the process used to make ethylene and 
propylene by thermal or steam cracking of 
hydrocarbon feedstocks. Pyrolysis gaso- 
line is catalytically treated in two 
stages to saturate the olefins present 
and to remove sulfur; cobalt catalysts 
are used in the second stage. Nickel- 
molybdenum catalysts can also be used for 
pyrolysis gasoline processing. There is 
currently no reclamation of cobalt from 
pyrolysis gasoline catalysts. 

The production of some organic acids 
also uses small quantities of cobalt cat- 
alysts. Acetic acid produced via high- 
pressure methanol carbonylation uses 
cobalt acetate and iodine as catalysts; 
adipic acid production uses cobalt naph- 
thenate or stearate in the first oxida- 
tion step; benzoic acid production may 
also use a cobalt catalyst. Many other 
routes to organic acids are in commercial 
practice so the use of cobalt can be cir- 
cumvented. The status of reclamation of 
organic acid catalysts is unknown. 

Possibilities exist for increased use 
of cobalt catalysts in hydrotreating and 
shale oil processing, but it is possible 
to use nickel catalysts in place of co- 
balt in these processes with nearly equi- 
valent results. 

Paint Driers (24-25) 

The role of cobalt in oil-base paint 
formulations is that of a catalytic agent 
surface drier. The drier is usually de- 
rived from cobalt metal reacted with an 
organic acid in water for chemical re- 
activity and dispersed in mineral spirits 
for physical solvency and convenient 
liquidity at concentrations of 6 to 24 
pet Co. The function of the organic acid 



is to form a cobalt soap that is solu- 
ble in the diverse range of paint media 
with minimal concomitant detracting prop- 
erties for the particular application. 
The drying process involves the conver- 
sion of the liquid to a solid by a chem- 
ical oxidation mechanism. Cobalt soap 
is usually preferred over manganese, ce- 
rium, iron, and zirconium soaps in the 
class of "top driers" in terms of speed 
of reduction and disappearance of sur- 
face tack, product discoloration, and 
durability. Top driers are complemented 
by "bottom driers" (usually soaps of 
lead, zinc, calcium, potassium, or zirco- 
nium) which hasten the solidification of 
the liquid coating down through the film 
to the substrate. 

Cobalt is the most effective surface 
drier additive in oil-base paints. The 
amount of cobalt used is typically 0.05 
pet (range 0.01 to 0.05 pet). To attain 
the same drying speed more manganese 
is usually needed, but this results in 
more discoloration and poorer durabil- 
ity. Iron has been used only where its 
inherent brown hue is acceptable. Ce- 
rium and zirconium have some favorable 
properties, but none is an alternative 
to replace cobalt directly on a one-to- 
one basis. Replacement is hampered not 
only by the complexity of the chemical 
mechanisms of paint formulation and deg- 
radation, but also by the vast diversity 
of types of paints. If cobalt were eli- 
minated or reduced there would be attend- 
ant costs in convenience and product 
quality in most cases. The dissipative 
nature of the product obviously precludes 
reclamation. 

Other Chemicals (24) 

Pigments 

Cobalt aluminate and silicate and asso- 
ciated oxides of other transition met- 
als provide a range of violet, blue, and 
green inorganic pigments, with ultimate 
resistance to high heat, light, and 
bleeding (organic solubility) , as well 
as special infrared reflectance. Mili- 
tary insignia and camouflage command 
high priorities for cobalt colors. With 
the exception of camouflage, all other 



15 



uses could be 
manganese and 
are potential 
applications . 



considered nonessential; 
other transition metals 
substitutes in several 



tapes; cobalt oxide is used for varistors 
and thermistors. 

Rubber Tires 



Ground-Coat Frit 

Cobalt oxide (0.1 to 1 pet) is used 
by the porcelain enamel industry to en- 
hance the adhesion onto metal of alkali 
alumino-borosilicate glasses, which are 
ground into frits. Cobalt-base frit is 
the preferred coating, but there has al- 
ways been some nickel oxide used along 
with the cobalt oxide. The cobalt oxide 
component can be diminished and the nick- 
el oxide component increased, but frits 
made with very low cobalt oxide content 
and high nickel content display inferior 
durability. 

Glass Decolorizers 

Cobalt is used to neutralize the color- 
ing of impurities such as iron and chro- 
mium in an average glass batch. Cobalt 
is needed where glass has to be optically 
clear. 

Miscellaneous 



Accelerators and Stabilizers 



rated polyes- 
laminates , and 
izes a 12-pct 
a promoter to 
e and related 
laminates have 
cobalt because 
lightly higher 



The production of unsatu 
ters for use in gel coats, 
compression moldings util 
cobalt octoate solution as 
influence the time of cur 
properties. Gel coats and 
the more critical need for 
they cure at ambient or s 
temperatures . 

Animal Feeds 



Cobalt has been used as a trace mineral 
diet additive in the United States for 
cattle, sheep, hogs, and poultry to en- 
able the animals to generate vitamin B 12 
for increased growth. 

Electronics 

In electronics, soluble cobalt salts 
are used for magnetic audio and video 



In the manufacture of steel-belted ra- 
dial tires, the presence of cobalt en- 
hances the adherence of rubber to steel. 

Battery Manufacturing 

Cobalt imparts improved recharging 
characteristics to power cells and 
nickel-cadmium batteries. 

Other Minor Chemical Uses 



Cobalt chemicals are also used in small 
quantities in several other minor uses: 
electroplating and electroref ining, des- 
iccant indicators, nucleating agents in 
investment casting, promoters in water 
treatment, chemical fuels, components in 
special oil drilling muds, etching tool 
steels, printing inks, and fertilizers. 

Cobalt used as chemicals other than 
catalysts could be reduced by 20 pet 
without much difficulty. Further reduc- 
tions could come from the rubber tire and 
battery sectors. However, some uses do 
require cobalt to accomplish the desired 
effect. Consumption of cobalt in the 
"miscellaneous" category could be reduced 
by 40 pet without serious consequences. 
Overall, a reduction of 60 pet could be 
achieved for "other chemicals." 

SUPPLY ALTERNATIVES 

Domestic (24, 29-30) 

The Bureau of Mines has evaluated 24 
domestic cobalt-bearing deposits with re- 
gard to the feasibility of cobalt recov- 
ery either as the principal product from 
sulfide or nickel-cobalt laterite occur- 
rences, or as a byproduct of lead or 
copper. Six of these sites are active 
mines, all currently producing lead in 
Missouri, but no attempt is made to ex- 
tract the cobalt contained in the ore; 
instead it is lost to the tailings and 
slag. Cobalt recovery would require the 
addition of another process circuit and 
incur added smelting and refining costs. 



16 



Basically, the technology exists to pro- 
duce primary cobalt from domestic 
sources, but the Bureau has concluded 
that higher prices (cobalt, $25/lb; cop- 
per, $l/lb; lead, $0.40/lb) are neces- 
sary to supply a significant percentage 
of U.S. cobalt consumption. Not only are 
the economics presently unattractive, but 
the time required to bring new domestic 
mines into production has been estimated 
at 5 yr or more. If circumstances even- 
tually do favor cobalt production in the 
United States, two relatively high-grade 
deposits which have been mined for cobalt 
previously, the Blackbird Mine in Idaho 
and the Madison Mine in Missouri, are 
considered to be likely candidates for 
development (table 3), but intensive min- 
ing efforts would rapidly deplete these 
modest resources. 

Despite current prices, California 
Nickel Corp. recently announced plans to 
build a demonstration plant in 1984 to 
extract nickel and cobalt from its nickel 
laterite deposit near Gasquet Mountain, 
CA. Construction of a commercial-scale 
plant is planned for 1987 (31). The U.S. 
Air Force, seeking to develop a secure 
source of cobalt suitable for use in mak- 
ing superalloys, has been considering re- 
questing proposals for a pilot plant to 
process native cobalt ore (32) . The only 
cobalt refinery in the United States at 
present is owned and operated by AMAX, 
Inc. , in Louisiana with a capacity of 2 
million lb of cobalt annually (33) . The 
refinery treats foreign cobalt-containing 
nickel matte. 

A Bureau research effort indicates that 
the heap-leaching method of recovering 
copper, which currently accounts for 
about 18 pet of U.S. copper production, 
may provide an opportunity for cobalt ex- 
traction. Passing the leach solutions 
through resin columns, washing with sul- 
furic acid, and extracting with solvent 



produces a concentrated cobalt solution. 
Further Bureau work will focus on the 
economic feasibility of the process (34). 

Foreign (24, 30 ) 

Cobalt is almost universally recovered 
as a byproduct of other mining and refin- 
ing operations , so the potential for in- 
creasing cobalt output is ultimately lim- 
ited by the economics of the metal of 
principal importance. The historic price 
levels of 1978-80 provided an incentive 
for increasing byproduct capacity, espe- 
cially from nickel resources. 

The copper mines of Zaire and Zambia 
remain the most important sources of 
world cobalt production, together provid- 
ing about 60 pet of the total. Zaire 
possesses the richest cobalt ores in the 
world (0.3 to 0.5 pet). Zambian ore 
grades range from 0.1 to 0.2 pet, and ac- 
cumulated copper smelter slags grade out 
at 0.6 pet, presenting another potential, 
although currently uneconomic, source of 
supply. 

Most of the remaining cobalt production 
from market economy countries is a by- 
product of nickel sulfide and laterite 
mining in Australia, Canada, the Philip- 
pines, Botswana, and New Caledonia; a 
great deal of New Caledonian cobalt is 
now lost because of the production pro- 
cess, which yields ferronickel. Some of 
the Canadian production is refined in 
Norway, while all of the cobalt from the 
other four sources is exported to Canada, 
Japan, France, or the United States for 
refining. Finland's cobalt production 
is derived from both copper and nickel 
sources , while the Republic of South 
Africa extracts some cobalt from plat- 
inum-group metal operations. Morocco had 
been producing cobalt as a principal 
product, but reserves there have been 
virtually depleted. 



TABLE 3. - Principal U.S. cobalt resources 



Location 


Owner and/or operator 


Ore grade, 


pet 


Blackbird Mine, 


Hanna Mining Co., 


0.55 




Idaho. 


Noranda Exploration Inc. 






Madison Mine, 


Anschutz Uranium Corp. 


.25 




Missouri. 









17 



Nickel sulfide ores currently represent 
the major source of cobalt from which 
production could be increased in the near 
future, but the large cobalt resources in 
nickel laterites, occurring mainly in New 
Caledonia, Indonesia, the Philippines, 
and Cuba, could eventually become the 
most important land-based source of co- 
balt. Of all the North American cobalt 
resources, Canadian nickel deposits have 
the greatest potential for being competi- 
tive alternatives to existing cobalt sup- 
ply sources. 

Ocean Minerals (24) 

Deep-sea manganese nodules typicalLy 
contain 0.1 to 0.5 pet Co. Marine manga- 
nese crusts, some containing perhaps 
1 pet Co at relatively shallow depths 
(less than 2,500 m) , have been located in 
the Pacific Ocean south of Hawaii, and in 
the Atlantic Ocean off the southeastern 
shore line of the United States. Assess- 
ments of these occurrences are in pro- 
gress. The current impediments to ocean 
mining have been discussed previously. 

Stockpile (30) 

In 1981 the General Services Admini- 
stration (GSA) purchased 5.2 million lb 
of cobalt from Zaire for the National De- 
fense Stockpile. By yearend 1982 deliv- 
ery was completed. In 1983 GSA purchased 
6.5 million lb of cobalt for the stock- 
pile, with delivery expected to begin 
early in 1984. Zaire will supply 4 mil- 
lion lb and Zambia the remainder, all at 
$5.50/lb. GSA awarded a contract for an 
additional 0.5 million lb at S11.70/lb 
to Inco, Ltd., of Canada in 1984 (35) . 

A panel of industry experts assembled 
by the American Society for Metals at the 
request of the Federal Emergency Manage- 
ment Agency determined that the recently 
acquired cobalt meets the quality re- 
quirements of current technology for the 
most critical defense and industrial ap- 
plications, but the present condition of 
the cobalt purchased during 1947-61 pre- 
cludes its use for producing vacuum- 
processed alloys. However, domestic ca- 
pability (process and equipment) exists 



to upgrade the quality of the pre-1980 
cobalt (36). 

SUMMARY OF DEMAND AND SUPPLY ALTERNATIVES 

The price increases of 1978 caused a 
substantial reduction in the amount of 
cobalt used in applications where eco- 
nomic alternatives were readily avail- 
able. Another round of high prices would 
lead to further substitution, but not 
with the facility experienced previously. 

Current essential U.S. cobalt needs 
are estimated at about 50 pet of present 
consumption. Existing substitution, pro- 
cessing, recycling, and design technology 
is capable of achieving cobalt savings of 
over 10 million lb annually by the next 
decade, based on an estimated consumption 
level of 22 million lb. 

Significant amounts of cobalt in super- 
alloys could be replaced, but this would 
require costly and time-consuming alloy 
optimization and engine certification 
programs . 

A great deal of substitution for cobalt 
in magnetic applications has already oc- 
curred. An estimated 20 pet of current 
cobalt use in these applications is es- 
sential and would continue at even a ten- 
fold price increase. 

Cobalt is a key requirement for ce- 
mented carbides, which are critical to 
high productivity in metal cutting and 
forming, mining, oil and gas well drill- 
ing, and other industrial operations. 
Cobalt-free materials cannot be consid- 
ered as practical general alternatives. 

In wear-resistant applications cobalt 
is required only for protection against 
galling and cavitation erosion, and even 
for these uses lower cobalt substitutes 
will suffice. 

Cobalt-free grades of high-speed tool 
steels and maraging steels have been 
developed. 

Hydrotreating is the catalytic process 
most amenable to substitution by cobalt- 
free materials. 

Cobalt is the single most effective 
surface drier additive in oil-base 
paints. Elimination or reduction of co- 
balt would incur substantial penalties in 
convenience and product quality. 



18 



A 60-pct reduction in the amount of co- 
balt used in other chemical applications 
could be accomplished. 

Most in-house and prompt industrial 
scrap is recycled, and cobalt is gener- 
ally recovered. 

Obsolete, low-grade, and mixed alloy 
scrap is not efficiently recycled. Some 
better quality obsolete scrap is recy- 
cled for superalloys, but a large quan- 
tity is downgraded. Most low-grade scrap 
(dusts, mill scale, grindings) is down- 
graded also, and its cobalt content is 
lost. Treatment of mixed-alloy scrap to 
recover all contained elements is tech- 
nically feasible but not economically 
practicable. 



Near-net-shape technologies can achieve 
improved yield of usable product from raw 
materials. 

Zaire and Zambia should continue to be 
the dominant suppliers in the world co- 
balt market. 

The technology exists to produce cobalt 
metal from domestic deposits, but total 
production costs would be at least $20/ lb 
to $25/ lb, and the time required would be 
at least 5 yr. 

Of all the potential North American co- 
balt resources, Canadian nickel deposits 
have the greatest potential of being com- 
petitive alternatives to existing cobalt 
supply sources. 



CHROMIUM 



BACKGROUND 

The uses of chromium encompass three 
major areas — metallurgical (as an alloy- 
ing element that imparts a variety of im- 
portant properties to many ferrous and 
nonferrous alloys, principally stainless 
and full-alloy steels) , refractory (chro- 
mite refractory bricks to line metallur- 
gical furnaces, glass regenerators, and 
rotary kilns) , and chemical (mainly pig- 
ments , plating, and leather tanning). 
Tables 4 and 5 quantify these uses. Pro- 
duction of chromite ore in the United 
States ceased after 1961 (except for 
a small amount produced for export in 
1976), and at present, domestic chromite 
resources are considered to be uneconomic 
to develop. Therefore, all chromite con- 
sumed in the United States is imported, 
mainly from the Republic of South Africa 
and the Philippines. Historically chro- 
mite has been classified into three 



general grades associated with the major 
end-use categories , but considerable in- 
terchangeability among the grades has 
evolved. Current nomenclature reflects 
the composition of the ore (high-chro- 
mium, high-aluminum, high-iron) rather 
than end use. 

In addition to chromite, substantial 
quantities of chromium are also imported 
as ferroalloys, predominantly high-carbon 
f errochromium, which is the typical form 
used to add primary chromium to steel. 
World ferroalloy production capacity has 
been shifting to ore-producing countries. 
As a result, imported chromium ferro- 
alloys have been steadily increasing 
their share of total chromium imports 
relative to chromite, and of total U.S. 
chromium ferroalloy supply at the ex- 
pense of domestic production (table 6), a 
trend which threatens the viability of 
the U.S. ferroalloy industry. 



TABLE 4. - U.S. consumption of chromite, by primary industry 





1981 


1982 


1983 


Industry 


Gross 
weight , 
10 3 st 


Average 
Cr 2 3 , 
pet 


Gross 
weight, 
10 3 st 


Average 
Cr 2 3 , 
pet 


Gross 
weight , 
10 3 st 


Average 
Cr 2 3 , 
pet 




503 
148 
238 


35.7 
37.3 
42.6 


270 

80 

195 


35.1 
36.4 
44.9 


64 

72 

189 


39.3 
36.9 

44.7 




889 


37.9 


545 


38.8 


325 


41.9 



19 



TABLE 5. - U.S. consumption of chromium ferroalloys and metal, by end use 

(Thousand short tons, gross weight) 



End use 



Ferrochromium 



Ferrochromium 
silicon 



Metal and 
other 



Total I 



1981 

Carbon steel 

Stainless and heat-resisting steel. . 

Full-alloy steel 

High-strength low-alloy and electric 

steel 

Tool steel 

Cast iron 

Superalloys 

Welding materials (structural and 

hardf acing) 

Other alloys 

Miscellaneous 

Total' 

Chromium content 

1982 

Carbon steel 

Stainless and heat-resisting steel.. 

Full-alloy steel 

High-strength low-alloy and electric 

steel 

Tool steel 

Cast iron 

Superalloys 

Welding materials (structural and 

hardf acing) 

Other alloys 

Miscellaneous 

Total 1 

Chromium content 

1983 

Carbon steel 

Stainless and heat-resisting steel.. 

Full-alloy steel 

High-strength low-alloy and electric 

steel 

Tool steel 

Cast iron 

Superalloys 

Welding materials (structural and 

hardf acing) 

Other alloys 

Miscellaneous 

Total' 

Chromium content 



8 
287 

71 

7 

4 

10 

7 

2 
2 
2 



400 
238 



6 
181 

37 

5 
2 

7 
6 

1 
1 
1 



247 
147 



7 

305 

33 

5 
4 
6 

7 

1 
2 

1 



371 
219 



1 

14 

4 

2 
( 2 ) 
( 2 ) 

W 


( 2 ) 
( 2 ) 



22 



1 

10 

3 

2 
( 2 ) 
( 2 ) 

( 2 ) 

W 
( 2 ) 
( 2 ) 



15 
5 



( 2 ) 

12 

2 

2 

W 

( 2 ) 

W 

w 

( 2 ) 
( 2 ) 



16 

6 



( 2 ) 

( 2 ) 

3 

3 


1 
2 

( 2 ) 

2 
( 2 ) 



11 
7 



( 2 ) 
( 2 ) 

1 

1 



( 2 ) 

2 

( 2 ) 

1 
( 2 ) 




( 2 ) 

( 2 ) 

( 2 ) 

( 2 ) 

( 2 ) 

3 

( 2 ) 

1 
( 2 ) 



9 

302 

79 

12 
5 

11 
9 

2 
4 
3 



434 
253 



6 

191 

41 

8 
2 
7 



268 
157 



8 
318 

34 

7 

4 

6 

10 

1 
3 
2 



392 
229 



W Withheld to avoid disclosing company proprietary data; 
Miscellaneous . 

Data may not add to totals shown because of independent rounding, 
2 Less than 1/2 unit. 



included with 



20 



TABLE 6. - Domestic production and imports of chromium ferroalloys and chromite 

(Thousand short tons) 





Chromium ferroalloys ] 


Chromite: Imports 


Year 


Domestic production 


Imports 


Gross 
weight 


Cr 2 3 
content 


Chromium 




Gross 
weight 


Chromium 
content 


Gross 
weight 


Chromium 
content 


content 


1963 


300 
418 
226 
119 
36 


180 

260 

127 

69 

19 


30 
180 
443 
150 
285 


21 
113 
255 

89 
167 


1,391 
931 
898 
507 
190 


605 
412 
368 
209 
86 


414 


1973 


282 


1981 


252 


1982 


143 




59 



Includes high- and low-carbon ferrochromium, 
chromium metal. 



f errochromium-silicon, and 



Calculated apparent consumption of 
chromium in all forms was 329,000 st in 
1983. This represented only a slight in- 
crease over the 1982 total, which was the 
lowest amount since the 1950' s, basically 
reflecting the recent performance of the 
steel industry. Chromium demand attained 
its highest level in 1974 at 625,000 st. 
In 1983 prices for chromite (f.o.b.) were 
$48/mt to $52/mt from the Republic of 
South Africa and $110/mt from Turkey; the 
price of imported 50- to 55-pct high- 
carbon ferrochromium ranged from $0,355/ 
lb to $0.40/lb. Total domestic chromium 
demand is forecast to grow at an average 
annual rate of 2.2 pet from 1981 to 2000. 
Table 7 contains world production and 
reserves of chromite, and chromium im- 
ports by the United States, as ore and 
f er rochromium . 

USES AND DEMAND ALTERNATIVES 

Metallurgical 

Prior to identifying the specific sub- 
stitution and surface modification meth- 
ods that can save chromium, the conserva- 
tion role of modern steel-making process 
technologies and novel metallurgical 
techniques also should be examined ( 18 , 
25-2£, 37-40). 

Although continuous casting is well 
established, opportunities exist for fur- 
ther application. The process results 
in significantly higher product yields, 



improved product quality, and cost advan- 
tages over ingot casting. Use of contin- 
uous casting in conjunction with the 
argon-oxygen decarburization (AOD) pro- 
cess has been credited with improving 
chromium yield in stainless steels by 10 
to 15 pet. AOD uses the furnace for 
melting only — a separate vessel accommo- 
dates decarburization and refining. Oxy- 
gen and argon are introduced to oxidize 
and remove carbon, thus achieving low 
carbon content while minimizing the oxi- 
dation of chromium and other elements and 
subsequent loss to slag. This greatly 
reduces the need for additions of low- 
carbon ferrochromium to obtain the de- 
sired composition, permits the use of 
cheaper raw materials (high-carbon ferro- 
chromium, more scrap), and results in 
lower costs for energy (because of re- 
duced operating temperatures). 

Wider application of duplex refining 
systems, some utilizing special melting 
and remelting techniques , appears to be 
a promising means of achieving substan- 
tial conservation of chromium. Cost- 
competitive steels that possess proper- 
ties comparable or superior to those of 
traditional steels can be produced with- 
out using large amounts of alloying ele- 
ments or elaborate heat treatment. This 
requires an understanding of the specific 
influence of the various fabrication- 
process variables on steel microstructure 
and the resultant properties that can be 
predicted. 



21 



TABLE 7. - World chromite mine production, reserves, and U.S. imports 

(Thousand short tons) 



Country 



Mine output 



1981 



1982 p I 1983 e 



Reserves 



Chromite 2 



U.S. impo r t s 



1981 



1982 



1983 



Ferrochromium 5 



1981 



1982 



1983 



Albania 

Belgium 

Brazil 

Canada 

China 

Cuba 

Cyprus 

Finland 

France 

Germany, Federal 

Republic of ... . 

Greece 

India 

Iran 

Italy 

Japan 

Korea , 

Republic of ... . 

Madagascar 

New Caledonia. . . 

New Guinea 

Norway 

Pakistan 

Philippines 

South Africa, 

Republic of ... . 

Spain 

Sudan 

Sweden : 

Turkey ' 

L/»o«_/«r\» • ■ • • • • •• 

United Kingdom.. 

Vietnam 

Yugoslavia 

Zimbabwe 

Total 



937 


260 





23 

11 

454 





47 

369 

35 


12 



110 
4 



1 

484 

3,164 



29 



466 

2,646 



17 

( 4 ) 

591 



965 



304 





30 

11 

380 





46 

374 

45 


12 



100 

55 





1 

391 

2,385 



28 



448 

2,701 



18 



476 



990 



310 





35 

11 

375 





45 

400 

55 



9 



100 

100 





1 

365 

2,460 



30 



440 

2,700 



20 



475 



2,000 



9,000 





NA 

1,000 

19,000 





NA 

15,000 

4,000 



NA 



NA 

2,000 





1,000 

23,000 

910,000 



NA 



5,000 

17,000 



NA 

NA 

19,000 



14 







78 










18 


( 4 ) 




145 

482 




49 
111 







4 






45 










41 



3 
70 

277 



32 
34 







6 


6 














21 




13 

144 





( 4 ) 









( 4 ) 

21 

3 




2 

5 



1 
1 





2 

2 

261 

1 



11 

8 







47 

62 



9,660 



8,770 



8,921 



'1,000,000 



898 



507 



190 428 



e Estimated. 

Preliminary. 
NA Not available. 

Shipping-grade ore (deposit quant 
high-chromium and high-iron chromite; 
^Average Cr 2 3 content: 1981 — 41.0 
3 Average chromium content: 1981 — 5 
4 Less than 1/2 unit. 
^Rounded. 







17 

( 4 ) 
6 





4 



( 4 ) 
( 4 ) 






( 4 ) 



( 4 ) 

55 





4 

6 



( 4 ) 



16 

33 



141 



4 

4 ) 
8 

4 ) 





( 4 ) 

2 



( 4 ) 



1 




1 




152 

( 4 ) 



11 

15 



( 4 ) 



33 

53 



280 



ity and grade normalized to 45 pet Cr203 for 
35 pet Cr 2 03 for high-alumina chromite). 
pet, 1982—41. 2 pet, 1983—45. 3 pet. 

7.8 pet, 1982—60.0 pet, 1983—58.2 pet. 



22 



Powder metallurgy also offers possibil- 
ities for chromium conservation. The use 
of powder formed by rapid solidification 
enables production of alloys with unique 
microstructures , and therefore, with 
properties not attainable with conven- 
tional metallurgical techniques. Near- 
net-shape technology minimizes material 
and energy use through reduced scrap 
generation. 

Stainless Steels (J_8, 25-26, 37-40) 

The largest use for chromium is the 
production of stainless and heat-resist- 
ing steels. Stainless steels actually 
are defined by their chromium content. 
Austenitic stainless steels constitute 
about 70 pet of U.S. stainless steel pro- 
duction, generally contain 17 to 36 pet 
Cr , and are used for many industrial pro- 
cessing, energy generation, pollution 
control, cryogenic, marine, transporta- 
tion, construction, and consumer product 
applications; martensitic stainless 
steels account for about 25 pet of domes- 
tic production, usually contain 11.5 to 
18 pet Cr , and are used as a lower cost 
alternative to austenitic types in surgi- 
cal instruments and some intermediate- 
temperature and oil industry applica- 
tions; ferritic stainless steels average 
slightly higher chromium contents than 
martensitic types, but are used mostly 
for decorative purposes. Heat-resisting 
steels usually are included with stain- 
less steels although they contain only 4 
to 10 pet Cr; they can be substituted for 
stainless steels in certain instances. 

Chromium provides passivation in iron- 
base alloys, and a minimum of about 12 
pet Cr is required for this purpose. 
Additional chromium increases the resist- 
ance of iron-base alloys to corrosion and 
oxidation by various degrees. Another 
function of chromium in austenitic stain- 
less steels is to stabilize the struc- 
ture. Because chromium has been a read- 
ily available, low-cost element, and 
because some higher chromium steels offer 
outstanding fabricating characteristics, 
stainless steels have been designed into 
a large number of applications. Chro- 
mium savings could be accomplished by 



partially replacing the chromium in ex- 
cess of 12 pet with other alloying ele- 
ments, by completely replacing stainless 
steel with a different material contain- 
ing little or no chromium, by employing 
thinner gauge or longer lasting high- 
chromium alloys, or by using surface mod- 
ification techniques, so that the prop- 
erties of chromium are utilized only 
where they are needed. Nevertheless, 
changes require careful evaluation of the 
service requirements for the particular 
application. 

Steels possessing lower chromium con- 
tent provide the least chromium savings, 
but their mechanical and fabricating 
characteristics can more closely approxi- 
mate those of the standard stainless 
steels. The loss in corrosion and oxida- 
tion resistance caused by the lower chro- 
mium content can be partly or completely 
compensated for by the addition of other 
alloying elements: 

1. For most applications 12 pet Cr 
will provide corrosion resistance. The 
function of chromium as an austenite sta- 
bilizer can be performed as effectively 
by manganese or nickel. In many chemical 
processes, however, the use of 12 pet Cr 
requires additions of molybdenum, sili- 
con, or aluminum to attain the corrosion 
resistance of type 304 stainless steel 
(the most widely used grade) . 

2. Austenitic stainless steels with 
about 14 pet Cr appear to have adequate 
strength and oxidation resistance for 
service up to 1,400° F. 

3. A composition of 12 pet Cr with 
silicon, aluminum, and nickel additions 
has corrosion resistance in aqueous envi- 
ronment and oxidation resistance in air 
superior to those of type 304 stainless 
steel. 

4. A 9Cr-lMo steel, modified by small 
additions of columbium and vanadium, is 
being tested as a replacement for 18-pct- 
Cr steels in steam powerplant heat ex- 
changers. A 9Cr austenitic stainless 
steel with molybdenum and possibly copper 
and vanadium, having corrosion resistance 
comparable to that of standard grades 
except in severe environments, appears 
feasible. 



23 



5. Modified 6-pct-Cr steels appear to 
be promising replacements for the 12-pct- 
Cr type in automotive emission control 
systems . 

6. High-strength duplex stainless 
steels and corrosion-resistant superfer- 
ritic stainless steels contain as much or 
more chromium than standard types, but 
afford reduced cross-section dimensions 
and less frequent replacement of 
components. 

Several no-chromium alternatives are in 
use or under development: 

1. Iron-manganese-alurainum alloys are 
being developed as potential substitutes 
for austenitic stainless steel grades in 
heat-resistant applications at moderate 
temperatures and some corrosion-resistant 
applications. Although brittle, they 
have been successfully used in furnace 
and ocean environments. 

2. Aluminum steels such as Fe-8Al-6Mo 
have demonstrated high-temperature oxida- 
tion resistance in air superior to that 
of type 304 stainless. 

3. High-silicon (9 to 18 pet) alloys 
of iron, cobalt, or nickel offer excel- 
lent resistance to corrosion but need im- 
provement with regard to mechanical prop- 
erties and fabrication. Smaller (1 to 4 
pet) additions of silicon are sufficient 
to enhance oxidation resistance. 

4. Silicon-molybdenum ductile iron has 
performed more effectively than high- 
chromium steels in high-temperature cor- 
rosive and/or erosive environments such 
as furnace grates and auto exhaust mani- 
folds. This material is a possible al- 
ternative to high-chromium steels in nu- 
merous high-temperature applications. 

5. Nickel-copper and nickel-molybdenum 
alloys may also be used for corrosion re- 
sistance with some sacrifice of perform- 
ance and mechanical properties. 

6. Metals such as titanium (seawater 
exposure, chemical apparatus), tantalum 
(chemical apparatus), aluminum, nickel, 
platinum, zinc, and zirconium, and non- 
metallic materials such as glass (excel- 
lent resistance to corrosive chemicals) , 
graphite (high strength), ceramics, and 
plastics have proven records in a num- 
ber of specialized functional and decora- 
tive applications. In most cases larger 
scale use is limited mainly by costs, 



availability, and complexities concern- 
ing fabrication and installation, but in- 
creased use of plastics appears to be a 
viable alternative to stainless steel, 
particularly where elevated-temperature 
service is not a factor. Plastics such 
as polyethylene, Teflon, and polyurethane 
have excellent resistance to corrosive 
chemicals and are readily fabricated into 
plant equipment. Glass mat or fiber re- 
inforcement provides some strength and 
extends applicability. 

Surface protection via cladding and 
coating techniques is an additional op- 
tion that can be used to prevent corro- 
sion, oxidation, and wear. This approach 
also offers the opportunity for consider- 
able reductions in the use of chromium- 
containing stainless steels: 

1. Cladding technology is well estab- 
lished. Individual strips of metal are 
passed through a pressure rolling mill to 
merge the lattices of the metals into a 
common structure; subsequent thermal 
treatment promotes diffusion, improves 
bond strength, and provides cold-work 
stress relief. Most active metals and 
alloys can be clad. Stainless-clad car- 
bon steels are used extensively in the 
chemical process industries for large 
columns and vessels. The initial cost is 
lower than for solid stainless, but usage 
is limited to configurations that can be 
made from sheet and plate, specialized 
joining techniques must be employed, and 
edges must be protected. Additional us- 
age is technically feasible but uneco- 
nomic at present. Cladding base steels 
with metals other than stainless steel 
could achieve even greater chromium 
savings . 

2. In contrast to wrought metal clad- 
ding, electroplating can be employed to 
obtain a chromium coating. Fabricated 
parts, brittle materials, and selected 
areas can be electroplated, but the majoc 
limitation is the size and shape of a 
component that can be plated. Chromium- 
rich diffusion coatings have been shown 
to be more widely applicable than 
electroplating, but item size and shape 
limitations also exist, as well as the 
requirement for high-temperature 
processing. 



24 



3. Directed energy beam techniques 
(ion beam processing, laser beam process- 
ing) can produce chromium-containing 
coatings which are metallurgically bonded 
to the surface with performance compar- 
able to or better than that of bulk chro- 
mium alloys. Since a vacuum or helium 
atmosphere is required, the substrate is 
limited in terms of size, and it must 
also be open and recess-free. 

4. The oxygen-diffused nitriding pro- 
cess (salt bath treating) has the capa- 
bility of producing a surface comparable 
or superior to that with chromium plating 
with respect to corrosion and wear re- 
sistance in many applications at similar 
cost. In addition, the discharge of none 
of the compounds present in the system 
effluent is restricted. 

5. Electroless nickel is an amorphous 
nickel and phosphorus coating applied via 
autocatalytic chemical reduction. It of- 
fers high strength, excellent abrasion, 
wear, and corrosion resistance (in most 
environments the corrosion resistance of 
hard chromium is much less) , uniform 
thickness, solderability , and ease of ap- 
plication. The petroleum and chemical 
process industries are the principal 
users of electroless nickel coatings. 

6. Some corrosion-resistant materials, 
such as elastomers and lead, are lim- 
ited to specialized lining applications. 
Their lack of strength must be compen- 
sated for by the structural capabilities 
of the basis material. Polymer concrete 
(concrete in which aggregate is bound in 
a dense matrix wifh a polymer binder) has 
demonstrated its utility as a liner for 
carbon steel exposed to corrosive geo- 
thermal brines, which chemically attack 
most conventional construction materials. 
Polymer concrete also offers a 10- to 20- 
pct cost reduction. 

Changes to less exotic chemical-process 
equipment can be made in some circum- 
stances through modifications to process 
chemistry by using inhibitors, making 
minor changes in the process stream, and 
eliminating contaminants. 

Stainless steel scrap is the major 
source of secondary chromium supply. 
Home scrap generated in the production 
process is retained and reused. Prompt 



industrial scrap can also be recycled ef- 
fectively if properly segregated, partic- 
ularly the stainless steels containing 
other high-value alloy metals. An opera- 
tion in Pennsylvania even recovers chro- 
mium and nickel in the form of remelt al- 
loy from plant particulate wastes, such 
as dusts, mill scale, and grinding swarf. 
Although there is considerable chromium 
in the waste products of some other met- 
allurgical industry processes, collection 
and processing costs hinder economical 
recovery on a large scale (except for su- 
peralloys) . The Bureau of Mines is ac- 
tively developing recycling technology in 
these areas (41) . Much obsolete stain- 
less steel scrap is downgraded or not 
recovered. Scrapped automobiles, partic- 
ularly the catalytic converter canister, 
represent a large source of available 
chromium. 

Alloy Steels U8, 25-26, 37-40) 

After stainless steels, the next 
largest metallurgical consumer of chro- 
mium is alloy steels, which owe their 
enhanced properties to a specified alloy 
content, often some combination of chro- 
mium, molybdenum, and/or nickel. Chro- 
mium influences hardenability — the prop- 
erty of a steel that determines the depth 
and distribution of hardness that may be 
induced by quenching — and can be present 
up to 1.7 pet. Alloy steels are used in 
structural engineering, machinery, and 
transportation equipment. Common AISI 
grades of these steels are the chromium- 
molybdenum 4100 series such as 4130 and 
4140, containing 0.8 to 1.1 pet Cr and 
used for fittings, valves, bolts, shafts, 
teeth, etc.; the nickel-chromium-molyb- 
denum 8600 and 8700 series such as 8620 
with 0.4 to 0.6 pet Cr, for use in gears; 
and the straight chromium 5100 series 
such as 5160 containing 0.7 to 0.9 pet 
Cr, used in coil and leaf springs. 

Historically, the basis for alternative 
alloy steels has been that of achieving 
equivalent hardenability as exemplified 
by the development of the National Emer- 
gency Steels during World War II, and the 
SAE EX steels during the Canadian mining 
strike and subsequent nickel shortage in 



25 



1969-70. In the last several years com- 
puterized hardenability prediction sys- 
tems have provided a rapid and highly 
accurate means of predicting the proper- 
ties of a steel as a function of composi- 
tion, thus offering the opportunity to 
design substitute alloys in less time 
by avoiding a lengthy program of melting 
and evaluating experimental compositions. 
(Two chromium-free steels, a manganese- 
molybdenum grade and a manganese-nickel- 
molybdenum grade, have been computer- 
designed under Bureau of Mines contract 
to be equivalent to the AISI 8600 and 
4100 steels.) While the use of chromium 
is highly efficient, many opportunities 
exist to eliminate or reduce the chromium 
content of these steels by using other 
alloying elements that also have a strong 
influence on hardenability, although in 
most areas the addition of these substi- 
tute elements carries an economic penalty 
relative to current chromium prices. 

The most commonly used carburizing 
steels contain 0.5 to 1 pet Cr for case 
and core hardenability, but several stan- 
dard chromium-free alternatives are 
available, usually with increased amounts 
of manganese and/or molybdenum. 

Through-hardening grades normally con- 
tain 0.5 to 1.5 pet Cr for hardenability 
and toughness, but manganese, molybdenum, 
boron, and silicon levels can be adjusted 
to produce chromium-free substitutes. 

Constructional alloy plate steels, used 
for bridges and other structures, have 
adequate chromium-free alternatives 
available, usually with higher molybdenum 
and boron content. 

Abrasion-resistant plate steels also 
have varieties without chromium, such as 
carbon-manganese , carbon-manganese-molyb- 
denum-boron, and carbon-manganese-molyb- 
denum-nickel-boron quenched and tempered 
alloys . 

Weathering plate steels, used in welded 
bridges and in buildings where weight 
savings and durability are required, usu- 
ally contain chromium, but some chromium- 
free types are available with increased 
nickel and copper levels. 

Low-alloy constructional cast steels 
have an average chromium content of 0.7 
pet, which can be adequately substituted 



for by increasing the levels of one or 
more other alloying elements such as man- 
ganese, nickel, molybdenum, or boron. 

Spring steels (0.7 to 0.9 pet Cr) and 
grinding mill ball steels (0.45 pet 
Cr) have chromium-free alternatives 
available. 

An alternative bearing steel with 0.4 
to 0.6 pet Cr offers superior processing 
and performance characteristics at lower 
cost compared with high-carbon grades 
containing 1.3 to 1.6 pet Cr. 

Ultra-high-strength steels are used 
principally in load-bearing aircraft 
forging applications that require high 
strength and good fatigue resistance. 
These steels all contain chromium (0.8 to 
1 pet) , and no known chromium-free sub- 
stitute alloys are available. Likewise, 
no substitutes are available for existing 
pressure vessel plate steels (0.5 to 2 
pet Cr to provide corrosion resistance) . 

Many different heat treatments are used 
to enhance the engineering properties of 
steel. Induction heating provides high 
energy density for controlled depth heat- 
ing, reducing the amount of heat that 
must be removed in the quenching pro- 
cess. Selective use can reduce or elimi- 
nate the need for hardenability-enhancing 
alloys in heat treating engineering 
steels. Applications other than harden- 
ing, such as induction treatment to pro- 
vide corrosion resistance, have been dem- 
onstrated experimentally. 

High-strength low-alloy (HSLA) steels 
generally do not contain chromium. Their 
scope could be extended to include areas 
reserved for heat-treatable chromium- 
containing steels. 

High-Strength Low-Alloy Steels 
08-39, _42-_43) 

High-strength low-alloy (HSLA) steels 
constitute a separate class of steels 
with high yield strength and good tough- 
ness, forraability, and weldability. 
These properties are achieved by using 
micro additions (less than 0.1 pet) of 
key alloying elements (most commonly co- 
lumbium, vanadium, and titanium) and con- 
trolled thermomechanical treatments. In 
some cases, other alloying elements, such 



26 



as molybdenum, nickel, and chromium, are 
also added, but the majority of HSLA 
steels do not contain chromium. 

Conventional low-alloy steels, contain- 
ing varying amounts of molybdenum, nick- 
el, and chromium, can attain equivalent 
or greater yield strengths, but they re- 
quire heat treatment and their higher 
carbon contents adversely affect tough- 
ness and weldability. Since HSLA steels 
achieve their strength without an in- 
crease (and usually with a substantial 
decrease) in carbon content, properties 
other than strength are preserved. 

HSLA steels have been used predominant- 
ly to meet a combination of requirements 
in pipeline service and for fuel-saving 
weight reductions in the automotive in- 
dustry. HSLA steels are becoming avail- 
able in an increasing number of forms for 
a variety of applications , including pos- 
sible displacement of chromium-containing 
heat treatable steels. 

Tool Steels ( 18 , 25, 37) 

The chromium content of tool steels 
ranges from 0.25 to 12.5 pet, but most 
contain 3 to 5 pet Cr. However, the 
total amount of chromium used in tool 
steels is small. The major use is in 
high-speed steels (cutting tools, hot- 
work dies) , in which chromium plays an 
important role in the hardening mecha- 
nism. In the high-carbon, high-chromium, 
cold-work steels (blanking, forming, 
drawing, and slitting tools) , chromium is 
essential for hardness and wear resist- 
ance. Sintered carbides perform ade- 
quately as substitutes in most cases (78 
pet) for these two types, but serious 
cost penalties are incurred. Replacement 
of chromium hot-work steels (dies forg- 
ing, molding, and extrusion tooling) is 
not feasible, and present technology does 
not indicate the development of chromium- 
free substitutes. Some of the other tool 
steels can be replaced by lower chromium 
steels or chromium-free materials, but 
the quantity of chromium involved is 
negligible. 



Alloy Cast Irons Q8, 37 ) 

Indefinite chill rolls with chromium 
contents of 1.5 to 2 pet are interchange- 
able with cast steel rolls with less than 
1 pet Cr or with spheroidal graphite 
rolls containing 0.4 pet Mo and no chro- 
mium. However, if these substitutions 
were made, roll performance in the mills 
would probably be reduced. 

Alternatives to abrasion-resistant cast 
irons, containing 15 to 28 pet Cr for 
abrasion and impact resistance, include 
NiHard type 2 (1.5 to 2 pet Cr) , NiHard 
type 4 (6 to 8 pet Cr) , wrought low-alloy 
steels, and chromium-molybdenum pearlitic 
or oil-quenched and tempered steels con- 
taining less than 2 pet Cr. Alloy combi- 
nations of manganese, boron, tellurium, 
molybdenum, and tungsten could also be 
considered as chromium replacements. 

Engineering castings contain 0.5 to 2 
pet Cr for wear resistance, strength, and 
dimensional stability in transportation 
applications. The trend in smaller sec- 
tion sizes is toward irons with less or 
no chromium, such as tin-molybdenum and 
copper-molybdenum irons. 

Superalloys (J_8, 25-26, 37, 39 ) 

Typically, wrought nickel-base and 
iron-nickel-base superalloys contain 15 
to 20 pet Cr; cast nickel-base, 10 to 15 
pet; and cobalt-base, 20 to 30 pet. The 
presence of chromium is essential in su- 
peralloys to provide the resistance to 
oxidation and hot corrosion required for 
gas turbine engines. However, the high 
chromium content is needed only at the 
surface, not for the mechanical proper- 
ties of the material. Ion implantation 
and laser annealing show the most promise 
to achieve the surface requirement for 
chromium while eliminating it from the 
bulk of the alloy. 

Scrap recycling technology is pursued 
in the superalloy field because of the 
relatively high value of these materials 
(44). 



27 



Other Alloys (1_8, 37_) 

In alloys of aluminum, titanium, and 
copper, chromium is used primarily to 
control microstructure and improve phys- 
ical and mechanical properties, but sub- 
stitutes for chromium are readily 
available. 

Aluminum-Base Alloys 

Chromium is used as a minor alloying 
addition in many of these high-perform- 
ance wrought alloys which are used in a 
variety of aerospace, marine, and surface 
vehicle load-bearing applications. The 
chromium alloying additions control re- 
crystallization behavior, help achieve 
consistent product performance, and im- 
prove resistance to stress corrosion 
cracking. Zirconium and manganese pro- 
duce effects that are similar to those 
produced by chromium, and replacement 
of the alloys containing chromium with 
chromium-free grades is possible in many 
applications. However, the slight per- 
formance penalties involved could be im- 
portant in some critical structural uses. 
Also of concern are the lead time and 
expense involved in qualifying materials 
for aerospace applications. 

Titanium-Base Alloys 

Chromium is used as an alloying addi- 
tion (2 to 11 pet) in several commercial- 
ly available titanium alloys. Chromium 
serves to stabilize the high-temperature 
beta allotrope of titanium. Other ele- 
ments (molybdenum, vanadium) also pro- 
duce similar effects and are frequent- 
ly used instead of or in combination 
with chromium. Therefore, chromium-free 
alloys are available with similar 
characteristics. 

Copper-Base Alloys 

Chromium additions (about 1 pet) pro- 
duce useful strengthening effects in 



copper alloys but do not exhibit partic- 
ularly unique property combinations. 
Apparently chromium-free grades could be 
substituted without significant cost or 
performance penalties. 

Refractory (1_8, 37"29, 45-46) — 
Chromite Refractories 



Chromite in the mineral (spinel) form 
imparts thermal shock and slag resist- 
ance, volume stability, and structural 
strength in refractories that range from 
all chromite to various mixtures of chro- 
mite and magnesia. They are designated 
as chrome (essentially all chromite) , 
chrome magnesite (chromite equal to or 
greater than the weight percent of magne- 
site) , and magnesite chrome (greater than 
50 wt pet magnesite). Refractories are 
supplied as granular material or shaped 
brick. The two major uses of chromite in 
granular form are as maintenance gunning 
mixtures for steelmaking furnaces and as 
facing sands in steel foundries. Substi- 
tute gunning materials include magnesite, 
dolomite, salvaged and reprocessed chro- 
mite, and chromium-free basic materials. 
Substitute materials for facing sands in- 
clude zircon, olivine, and silicon sands. 
Olivine is preferred for high-manganese 
steel castings. Silica sands are primar- 
ily used as backup, not facing, sands. 
The brick may be bonded chemically (un- 
burned) , burned, or fusion cast. 

The steel industry is the predominant 
consumer of chrome-bearing refractories. 
However, chrome ore usage appears signif- 
icantly less critical now than just a few 
years ago. The consumption of these re- 
fractories has been on a downward trend 
because of the continuing decline in 
open-hearth furnace steelmaking, which 
has been the principal user of chromite 
(table 8). The main replacement for the 
open-hearth process — the basic oxygen 
converter — uses refractories based only 
on periclase (MgO) with carbon. The 
other alternative, the electric furnace, 
does utilize chromite, but in the past 



28 



TABLE 8. - Steel production in the 
United States, by type of furnace 

(Percent) 



Year 


Open 


Basic oxygen 


Electric 




hearth 


converter 




'1963 


81 


8 


10 


1973 


26 


55 


18 


1981 


11 


61 


28 


1982 


8 


61 


31 


1983 


7 


62 


31 



Bessemer furnace production: 1 pet. 

several years the extensive application 
of water-cooled sidewall panels and roofs 
has reduced the need for chromite by 60 
to 70 pet. Most electric furnaces use 
brick made of periclase with carbon or 
graphite in the bottom, slag line, and 
interval from the slag line to the lower 
edge of the water-cooled panels. It is 
estimated that about 60 pet of installed 
electric furnace capacity in the United 
States is now water cooled, a practice 
that should steadily increase. Argon- 
oxygen decarburization and vacuum oxygen 
decarburization employ periclase-chrome 
or dolomite refractories. Apparently do- 
lomite is capable of totally replacing 
periclase-chrome in this application. 

Increased demand for higher quality 
steels has led to changes in ladle metal- 
lurgy and increased use of degassers and 
related processes, with a resulting pref- 
erence for chrome refractory usage. La- 
dles are increasingly lined with peri- 
clase-chrome or other materials rather 
than fireclay, and degassers are conven- 
tionally lined with periclase-chrome and 
alumina refractories. 

Glass, nonferrous, and rotary kilns 
also utilize chromite. For copper con- 
verters, higher chromium compositions re- 
portedly give better performance. In 
most other applications, substitution of 
magnesite chrome for chrome and chrome 
magnesite can be made at no penalty in 
performance and minimal increase in ini- 
tial cost. The extent of such substitu- 
tion could yield a savings in chromite 
consumption for brick well in excess of 
50 pet. 



Considerable potential exists for sal- 
vage and reuse of chromium-bearing brick 
in all consuming industries (18, 47-49). 
Chromium-bearing bricks in many units are 
distinctly different and recognizable 
from chromium-free refractories even af- 
ter use, so the bricks can be separated 

by hand and stacked separately for sal- 
vage, reprocessing, and reuse. Up to 33 
pet of the bricks in an original steel- 
producing structure can be salvaged by 
such practice. 

Chemicals (18, 37 ) 

Chemical-grade chromite ore is roasted 
with soda ash and lime to convert the 
Cr 2 3 to Na 2 Cr0 4 . This is leached with 
water to extract the soluble sodium chro- 
mate. Sodium chromate is acidified with 
sulfuric acid or carbon dioxide to pro- 
duce the principal chromium chemical, 
sodium di chromate. Most chromium chemi- 
cals are made from sodium dichromate. 

In 1982, the Environmental Protection 
Agency set out its final regulations in 
accordance with the Clean Water Act on 
pollutants discharged in wastewater from 
inorganic chemical plants. Included in 
regulation coverage are chrome pigments 
and sodium dichromate. The Bureau of 
Mines is developing process technologies 
for reducing chromium losses in certain 
chemical operations (50). 

Pigments and Paints 

The main chrome pigments are chrome 
yellow, molybdenum orange, zinc chromate, 
chrome green, and chrome oxide green. 
The primary uses for chrome pigments are 
for coloring plastics, for printing inks, 
and in paints for highway lines and in- 
dustrial finishes (vehicles, equipment, 
appliances) . Zinc chromate is used main- 
ly as a corrosion inhibitor primer for 
metals. Replacement of chromium pigments 
with proven nonchromium pigments to ob- 
tain the same color would involve a sub- 
stantial price penalty. The chrome pig- 
ments could be replaced by pigments such 
as carbon black, iron oxide, and titanium 



29 



oxide, but these substitutes would limit 
the number of colors. 

Leather Tanning 

Chromium compounds are used to tan 
the bulk, of the leather produced in the 
United States. Substitutes such as vege- 
table tanning compounds exact definite 
price and performance penalties. 

Metal Finishing and Treatment 

Chromium is used for chromium plating 
(decorative and engineering) and the 
treatment of copper, brass, zinc, and 
cadmium alloys, and galvanized steel. 
About 60 pet of the chromium consumed in 
electroplating is used in decorative end 
uses, 30 pet is used in engineering 
(hard) chromium plating, and the rest in 
other forms of metal finishing (chroraate 
conversion coatings, chromic acid anodiz- 
ing of aluminum). Obviously, decorative 
chromium plating could be discontinued — 
materials now being plated could be 
painted or made from chromium-free mate- 
rials such as plastics. Hard chromium 
plating is used for its excellent physi- 
cal properties, hardness, wear resist- 
ance, and low coefficient of friction. 
The only apparent substitute is electro- 
less nickel, which is better than hard 
chromium for wear resistance in certain 
applications. In addition, its "throwing 
power" is far superior, and it does not 
degrade the fatigue properties as hard 
chromium plating sometimes does. Another 
use for chromium plating is in the manu- 
facture of "tin-free steel" that can re- 
place tinplate in some canning uses. 
Only 15 to 20 pet of the chromic acid 
used actually ends up on the plate, and 
a considerable saving of chromium can 
be accomplished by recycling the wasted 
material. Plating baths using triva- 
lent chromium compounds in place of chro- 
mic acid would also yield savings from 
the use of less chromic acid spray and 
effluent. 



Drilling Mud Additives 

Sodium dichromate is used to produce 
chromium lignosulf onates for drilling 
muds; no satisfactory substitutes exist, 
especially for drilling deep wells (over 
10,000 ft). Chromium compounds also are 
used as a corrosion inhibitor in addi- 
tives to drilling muds to greatly extend 
the life of the drilling equipment. 

Water Treatment Compounds 

Sodium dichromate is used to make water 
treatment compounds such as corrosion in- 
hibitors for cooling towers and atr con- 
ditioners. The largest users are petro- 
chemical and chemical plants and oil 
refineries. No substitutes have been 
satisfactory as corrosion inhibitors at 
temperatures of 150° F or higher, such as 
are found in petrochemical and oil refin- 
ery operations. Substitutes are avail- 
able for less critical applications, such 
as air conditioners and cooling towers 
operating at 120° F or less, but they re- 
sult in a performance and price penalty. 

Wood Treatment Compounds 

Sodium dichromate is used to make 
copper-chromium-arsenic compounds to pro- 
tect wood against termites, fungus, etc. 
Other preservatives such as creosote 
and pentachlorophenol can be used to 
treat wood but in some cases would result 
in a performance penalty, primarily in 
paintability . 

Chemical Manufacture and Other Uses 

Sodium dichromate is used to manufac- 
ture other chemicals such as potassium 
dichromate, chromium organic complexes 
for treating textiles and paper, chromium 
dioxide for magnetic tapes, and chromium- 
containing catalysts for the synthesis 
of ammonia and methanol and for many hy- 
drogenation and polymerization reac- 
tions. In most cases no substitute is 



30 



known for these specific chromium uses, 
and the elimination of chromium would re- 
sult in a performance penalty in practi- 
cally all cases. 

SUPPLY ALTERNATIVES 

Domestic (18, 51-52) 

The Bureau of Mines assessed the via- 
bility of 34 nonlaterite and 9 nickelif- 
erous laterite deposits of chromite in 
the United States. Although some of 
these deposits have been in production in 
the past, none of them was considered 
suitable for development with existing 
technology at current market prices — 
domestic production of metallurgical- and 
chemical-grade chromite would require 
chromite market prices of about twice 
those prevailing in January 1981. The 
minimum lead time required to bring the 
various operations on-stream ranges from 
1 to 4 yr, and, based on domestic re- 
source estimates, production would be 
relatively small and of short duration. 
Most of the U.S. chromium resources occur 
in the Stillwater Complex in Montana as 
stratiform deposits, in northern Califor- 
nia as podiform deposits, and in the Ore- 
gon Beach Sands as placer deposits. 

Foreign (J_8, 39, 45, 52-54) 

Although world chromite reserves are 
substantial, they are highly concentrated 
in southern Africa — over 90 pet are held 
by the Republic of South Africa and Zim- 
babwe. Only a few countries, nearly all 
of which are in the eastern hemisphere, 
produce significant amounts of chromite 
(table 7), and of those, the U.S.S.R. and 
the Republic of South Africa are by far 
the leading producers, together approach- 
ing 60 pet of the total. From another 
perspective, centrally planned economy 
countries (essentially the U.S.S.R. and 
Albania) account for about 40 pet of 
world production. Present sources that 
appear capable of continuing as large 
producers of chromite well into the next 
century include the Republic of South 
Africa, Zimbabwe, the U.S.S.R., India, 
and Finland ( 54 ) . Announcements by sev- 
eral other countries of new chromite 



discoveries and projects to expand exist- 
ing capacity have increased the likeli- 
hood of modest decentralization of supply 
over the next decade or two. However, 
the vast chromite resources of southern 
Africa should ensure eventual concentra- 
tion of production in that region. 

The widespread adoption of argon-oxy- 
gen-decarburization (AOD) process steel- 
making opened the high-iron-content chro- 
mite of the Republic of South Africa 
to metallurgical use (and effectively 
blurred the traditional distinction among 
metallurgical-, refractory-, and chem- 
ical-grade ores) . Whereas f errochromium 
production had long been restricted to 
metallurgical-grade ore with its high 
chromium-to-iron ratio, AOD permits the 
utilization of high-carbon ferrochromiura 
(made from high-iron chemical-grade chro- 
mite) rather than the costlier low-carbon 
ferrochromiura. 

Conversion of chromite to f errochromium 
is being accomplished increasingly in the 
ore-producing countries, as is the con- 
struction and planning of new ferrochro- 
raium capacity, to accommodate both cap- 
tive needs and export markets. This is 
occurring at the expense of some of the 
traditional ferrochromium producers (who 
are also the principal consumers) — the 
United States, Western Europe, and Japan. 
The top chromite producers, the U.S.S.R. 
and the Republic of South Africa, are 
also the world's largest producers of 
ferrochromium, nearing half of the total, 
followed by Japan and Sweden. Not sur- 
prisingly, Zimbabwe also has established 
itself as a major ferrochromiura supplier. 
It is probable that world ferrochromium 
production capacity also will predominate 
in southern Africa in the long term. 

Stockpile (52) 

Inventories of metallurgical-, chem- 
ical-, and refractory-grade chromite ore 
are all well below National Defense 
Stockpile goals. However, an inventory 
of chromium ferroalloys in excess of the 
goal is held for offset against chro- 
mite. It was announced in December 1982 
that the General Services Administration 
(GSA) would begin a program of upgrading 
stockpiled chromite into high-carbon 



31 



f errochromium , and in June 1983 GSA so- 
licited bids to convert 125,000 st of 
stockpiled chromite into f errochromium. 

A panel of industry experts assembled 
by the American Society for Metals at the 
request of the U.S. Department of Com- 
merce conducted a quality assessment of 
the 7.5 million lb of chromium metal in 
the National Defense Stockpile. The pan- 
el concluded that the chromium metal held 
in the stockpile is not suitable for pro- 
ducing vacuum-melted superalloys for air- 
craft jet engines or other alloys which 
have stringent purity requirements for 
chromium metal as an alloying element. 
The panel also noted that the stockpile 
contains no high-purity f errochromium 
usable for aircraft superalloys (55) . 

SUMMARY OF DEMAND AND SUPPLY 
ALTERNATIVES 

Current U.S. chromium consumption could 
be reduced by approximately one-third by 
using available technology to substi- 
tute alternative materials and processes, 
to recover and recycle waste chromi- 
um, and to design for greater chromium 
efficiency . 

Chromium is essential for corrosion and 
oxidation resistance in stainless steels, 
but chromium savings can be accomplished 
in various stainless steel applications 
by partially replacing the chromium in 
excess of 12 pet with other alloying ele- 
ments, by completely replacing stainless 
steel with a different metallic or non- 
metallic material, by employing thinner 
gauge or longer lasting high-chromium al- 
loys, or by using surface modification 
techniques such as cladding, plating, and 
coating. 

Stainless steel scrap is the major 
source of secondary chromium supply. Al- 
though there is considerable chromium in 
the waste products of some other metal- 
lurgical industry processes, collection 
and processing costs hinder economical 
recovery on a large scale. 

The chromium content of alloy steels 
can be eliminated or reduced by using 
other alloying elements that also have a 
strong influence on hardenability . How- 
ever, no substitutes are available for 



existing ultra-high-strength or pressure 
vessel plate steels. 

Chromium plays an important role in 
the hardness and wear resistance of tool 
steels. Substitution with sintered car- 
bides entails serious cost penalties. 

Low- or no-chromium alternatives are 
available for roll, abrasion-resistant, 
and engineering alloy cast irons. 

The presence of chromium in superalloys 
markedly improves resistance to oxidation 
and hot corrosion. However, the high 
chromium content is essential only at the 
surface, not for the mechanical proper- 
ties of the material. 

In alloys of aluminum, titanium, and 
copper, chromium is used primarily to 
control microstructure and improve prop- 
erties, but substitutes for chromium are 
readily available. 

Continuous casting results in signifi- 
cantly higher product yields. Its use in 
conjunction with the AOD process has been 
credited with improving chromium yield in 
stainless steels by 10 to 15 pet. 

Wider application of duplex refining 
systems for steel production appears to 
be a promising process area for achieving 
substantial conservation of chromium. 

Powder metallurgy techniques as rapid 
solidification and near-net-shape offer 
possibilities for chromium conservation 
by producing unique properties via alloy 
microstructure and by generating less 
scrap. 

The importance of chrome-bearing re- 
fractories has diminished because of the 
continuing decline in open-hearth furnace 
steelmaking. 

Replacement of chromium pigments with 
proven alternatives would incur a sub- 
stantial cost penalty or limit the number 
of available colors. 

No practical substitutes exist for the 
chromium compounds that are used to tan 
the bulk of leather produced in the 
United States. 

The chromium used for decorative elec- 
troplating could be replaced by chromium- 
free materials such as plastics, or by 
painting the substrate. Electroless 
nickel provides an alternative to hard 
chromium plating. 



32 



No satisfactory substitutes exist for 
chromium compounds used in deep-well 
drilling muds. 

No chromium-free substitutes have been 
proven satisfactory as corrosion in- 
hibitors at temperatures of 150° F or 
higher such as are found in petrochemical 
and oil refining operations. Alterna- 
tives are available for less critical 
applications. 

Nonchromium wood preservatives are 
readily available, but do not offer com- 
parable paintability. 

Although some domestic chromite depos- 
its have been in production in the past, 



none is considered suitable for develop- 
ment with existing technology at current 
market prices. 

The known chromite resources of the Re- 
public of South Africa and Zimbabwe are 
so vast that eventual concentration of 
supply there is expected. 

With the trend toward conversion of 
chromite to f errochromium in the ore- 
producing countries, it is probable that 
future world ferrochromium produc- 
tion will also become highly concentrated 
in the Republic of South Africa and 
Zimbabwe . 



MANGANESE 



BACKGROUND 

The importance of manganese arises 
mainly from its desulf urizing, deoxi- 
dizing, and alloying functions in iron- 
making and steelmaking, which account 
for about 90 pet of its use. The minor 
areas of manganese use are dry cell 
batteries and chemicals (tables 9 and 
10). Manganese ore products containing 
35 pet or more Mn have not been produced 
domestically since 1970. Some manganese 
is produced in the form of low-grade 
(10 to 14 pet) manganif erous ores, but 
it satisfies only a very small amount 
of U.S. primary demand. The principal 
sources of recent manganese ore imports 
are Gabon, the Republic of South Africa, 
Brazil, Australia, and Mexico. Manganese 
ore was the dominant form in which manga- 
nese was imported until 1977. Imports of 

TABLE 9. - Consumption of manganese ore 
in the United States' 

(Thousand short tons) 



Use 


1981 


1982 


1983 


Manganese alloys and 


745 
148 

184 


412 
84 

113 


274 


Pig iron and steel.... 
Batteries, chemicals, 
and miscellaneous .... 


106 
151 




1,077 


609 


531 



Containing 35 pet or more manganese 
(natural) . 



manganese in upgraded forms, consisting 
for the most part of high-carbon ferro- 
manganese, have since been markedly 
greater than those of ore (table 11). 
The Republic of South Africa and France 
presently are the leading suppliers of 
manganese ferroalloys to the United 
States. (The implications for the domes- 
tic ferroalloy industry regarding the 
shift in imports from ore to processed 
form have been discussed previously.) At 
current prices there are no reserves of 
manganese ore in the United States con- 
taining 35 pet or more Mn or from which 
concentrates of such a grade could be 
commercially produced. Although technol- 
ogy for making ferromanganese from lower 
grade ores is available, the use of high- 
manganese content ores is far more cost 
effective. 

In 1983, the total consumption of man- 
ganese in the United States declined to 
668,000 st, the lowest quantity since 
before 1960, and far below the high of 
1,554,000 st in 1973. As with chromium, 
the recent sharp decline in manganese 
demand paralleled the drop in output 
of the steel industry. A representative 
average price for metallurgical ore con- 
taining 48 pet Mn was about $1.38 per 
long ton unit, c.i.f. U.S. ports in 1983, 
down from $1.58 in 1982. The average an- 
nual growth rate to the year 2000 for 
manganese demand in the United States is 
forecast at 1.6 pet (base year 1981). 



33 



TABLE 10. - Consumption by end use of manganese ferroalloys 
and metal in the United States 

(Thousand short tons, gross weight) 



End use 



Ferroraanganese Si licoraanganese 



Manganese metal 



1981 

Carbon steel , 

Stainless steel and heat-resisting 

steel 

Full-alloy steel , 

High-strength low-alloy steel , 

Electric steel , 

Tool steel , 

Cast iron , 

Superalloys , 

Other alloys , 

Miscellaneous and unspecified , 

Total 2 , 

1982 

Carbon steel , 

Stainless steel and heat-resisting 

steel , 

Full-alloy steel , 

High-strength low-alloy steel , 

Electric steel , 

Tool steel. , 

Cast iron 

Superalloys 

Other alloys , 

Miscellaneous and unspecified , 

Total 2 , 

1983 

Carbon steel , 

Stainless steel and heat-resisting 

steel , 

Full-alloy steel 

High-strength low-alloy steel 

Electric steel 

Tool steel 

Cast iron 

Superalloys 

Other alloys 

Miscellaneous and unspecified 

Total 2 



621 

12 

105 

60 

C 1 ) 

(') 

17 

W 

2 

2 



821 



329 

8 

45 

37 

(') 

(') 

13 

W 

2 

4 



439 



335 

15 

38 

37 

(') 

(') 

15 

W 

1 

4 



446 



95 

5 

31 

10 

(') 

(') 

9 

W 

3 

2 



156 



67 

3 

18 

7 

(') 

(') 

8 

W 

2 

1 



106 



50 

4 

13 

5 

(') 

(') 

8 

W 

1 

C 1 ) 



83 



3 

1 

1 
(') 
(') 
(') 
(') 
11 

1 



24 



2 

1 

1 
(') 
(') 
(') 
(') 

8 

C 1 ) 

17 



2 
1 

1 
(') 
( ] ) 
(') 
(') 

8 

1 



18 



W Withheld to avoid disclosing company proprietary data: 
ous and unspecified. 
'Less than 1/2 unit. 



included with Miscellane- 



Data may not add to totals shown because of independent rounding. 



34 



TABLE 11. - Domestic production and imports of manganese 
ferroalloys and manganese ore 

(Thousand short tons) 





Manganese ferroalloys ' 


Manganese ore: Imports 


Year 


Domestic production 


Imp 


orts 


Gross 
weight 


Mn 




Gross 


Mn 


Gross 


Mn 


content 




weight 


content e 


weight 


content 






1963 


e 922 


695 


e 173 


131 


2,390 


1,124 




893 


688 


438 


336 


1,510 


722 




390 


292 


808 


615 


639 


301 




207 


163 


560 


430 


238 


111 




2 86 


2 70 


488 


364 


368 


178 



e Estimated. 

includes f erroraanganese, silicomanganese, and manganese metal. 
2 Ferroraanganese only; silicomanganese and manganese metal production 
data withheld to avoid disclosing company proprietary data. 



World production of manganese, world man- 
ganese reserves, and exports to the 
United States are contained in table 12. 

USES AND DEMAND ALTERNATIVES 

Metallurgical (56-63) 

Iron and Steel 

Manganese is consumed both in ironmak- 
ing and steelmaking (fig. 1). The use of 
iron ore with a low manganese content re- 
quires additional manganese in the blast 
furnace for desulf urization, usually as 
some combination of manganese-containing 
iron ore, low-grade manganese ore, high- 
grade manganese ore fines, recycled slag, 
and scrap. Some manganese loss occurs in 
the slag, and, to a lesser extent, in the 
flue dust. The optimal hot-metal manga- 
nese level of 0.6 to 0.8 pet provides 
several beneficial effects during steel- 
making, such as enhanced desulf urization, 
increased yield, longer refractory life, 
and reduced flux consumption. Much of 
the manganese in the hot metal is lost 
during steel production, primarily to the 
slag. 

Molten steel contains dissolved sulfur 
and oxygen which generally impart unde- 
sirable properties if retained in the 
solidified steel. In the steelmaking 
process manganese ferroalloys are added 
either mostly in the furnace (open 
hearth) or after the metal has been 



tapped into the ladle (basic oxygen con- 
verter and electric furnace) in order to 
perform the essential roles of taking the 
sulfur and oxygen into the slag or com- 
bining with them in a more benign form in 
the final product. However, aluminum and 
silicon are better deoxidizers, so man- 
ganese usually is not used alone for de- 
oxidation. Aside from the function of 
tying up impurities, manganese improves 
the mechanical properties of steel by 



Fe and Mn ores 




"1 

Discard-^-] 



Casting 



FIGURE 1. - Flowsheet showing manganese 
inputs for production of steel by blast furnace- 
basic oxygen process. 



35 



TABLE 12. - World manganese mine production, reserves, and U.S. imports 
(Thousand short tons except as otherwise noted) 



Mine output 



Countrv 



Mn , pet 



1981 



1982 F 



1983* 



Reserves 
(Mn content) 



U.S. imports 



Mn ferroalloys 



l .2 



1981 



1982 



1983 



Manganese ore 5,4 



1981 



1982 



1983 



Australia 

Bolivia 

Brazil 

Bulgaria 

Canada 

Chile 

China 

France 

Gabon 

Germany, Federal 

Republic of ... . 

Ghana 

Greece 

Hungary 

India 

Indonesia 

Italy 

Japan 

Korea , 

Republic of ... . 

Mexico 

Morocco 

Norway 

Pakistan 

Philippines 

Portugal 

South Africa, 

Republic of . . . . 

Spain 

Sudan 

Thailand 

Turkey 

U.S.S.R 

United Kingdom. . 

Yugoslavia 

Zaire 



Total 



37-53 
28-54 
38-50 
30- 

32-35 
20 + 

50-53 



30-50 
48-50 
30-33 
10-54 
47-56 
30 
24-27 



27 + 

50-53 



35- 
30 + 



30-48+ 

48 
46-50 
27-46 
30-31 

30 + 
30-57 



1,555 

1 

2,251 

50 



28 

1,760 



1,640 



246 

6 

78 

1,682 

3 

10 

96 


637 
121 





( 6 ) 



5,555 

( 6 ) 

12 
16 
10,090 

34 
20 



1,248 

( 6 ) 

2,580 

50 



18 

1,760 



1,667 



176 

6 

91 

1,596 

20 

10 

86 


561 
106 





( 6 ) 



5,750 



( 6 ) 

9 

8 

10,830 



33 





1,491 

( 6 ) 

2,300 

50 



18 

1,760 



2,047 



210 

6 

94 

1,455 

19 

10 

85 


386 

81 




( 6 ) 



3,181 

( 6 ) 

7 
4 
11,500 

33 




51,600 

NA 

20,900 

NA 



NA 

15,000 



110,000 


4,000 

NA 

NA 

21,500 

NA 
NA 
NA 



3,500 

600 



NA 

NA 



407,000 



NA 

NA 

NA 

365,000 



NA 

NA 



6 



12 



62 



5 

189 





( 



( 6 ) 
46 

5 


33 

274 

10 









14 

14 





18 


44 


20 





104 



1 




10 


6 


40 

4 


20 

255 





17 
16 




16 


59 

3 


117 


6 






3 


42 


33 




28 

140 
6 





26 




NAp 



25,894 



26,607 



24,739 



1,000,000 



671 



555 



481 



66 


76 





180 











65 
25 





227 











639 



37 

6 

4 




46 











3 
9 





132 











238 



29 


79 





171 











64 
( 6 ) 





25 











368 



"Estimated . 
Preliminary. 
NA Not available. 
NAp Not applicable. 



Ferromanganese and silicomanganese. 

tent: 1981— fer 

t; 1983 — ferroma 

ese. 

tent: 1981—47.1 pet; 1982—46.7 pet; 1983—48.4 pet 



romanganese, 77.8 pet; 1982 — ferromanganese, 77.9 
nganese, 78.0 pet, silicomanganese, 65.9 pet. 



''Average manganese con 
silicomanganese, 66.2 pc 
3 35 pet or more mangan 
Average manganese con 
-Terromanganese only. 
'Less than 1/2 unit. 

Data may not add to totals shown because of independent rounding 
^Rounded. 



pet, 



36 



imparting alloying effects of increased 
strength, toughness, hardness, and 
hardenability . 

The bulk of manganese ferroalloys is 
consumed in the production of plain car- 
bon steel, and most of the remainder is 
used in the various alloy steels. With 
the exception of carbon, manganese is the 
least expensive means of adding strength 
to steel, and manganese even replaces 
carbon in high-strength low-alloy steels 
since high carbon content can adversely 
affect other properties. The manganese 
content of carbon and alloy steels ranges 
from a few tenths to less than 2 pet; 
stainless steels usually do not exceed 2 
pet Mn, but some require much higher lev- 
els; and high-manganese steels, such as 
Hadfield steel, may contain as much as 
14 pet Mn. The surface of Hadfield steel 
hardens under repeated impact, but its 
interior retains toughness and is there- 
fore used in railroad applications and 
mining and earthmoving equipment. 

The type of ferroalloy used to add 
manganese to steel is determined by cost 
and the technical constraints dictated 
by the desired products. High-carbon 
f erromanganese is normally used since it 
is considered the most economic form. 
Medium-carbon and low-carbon grades of 
f erromanganese are necessary where the 
carbon content of the steel is critical, 
but if the introduction of carbon could 
be detrimental, and silicon content is 
acceptable to the product requirements , 
silicomanganese is used. Silicomanganese 
is also less expensive than medium- or 
low-carbon f erromanganese, and the sili- 
con also acts as a deoxidant , leaving a 
greater amount of manganese in the steel. 

There is no practical substitute for 
manganese in steelmaking. Potential sub- 
stitutes for manganese as a steel desul- 
furizer include zirconium, titanium, and 
rare earth metals, and possibly calcium 
and magnesium, but these metals cannot be 
supplied in sufficient quantities at low 
prices. Likewise, equivalent properties 
can be obtained with other alloying met- 
als such as chromium, molybdenum, and 
nickel, but only at much higher cost. 

Past and present developments in steel- 
making technology have brought about 



manganese conservation. The phasing out 
of open-hearth steelmaking has resulted 
in a corresponding decline in unit manga- 
nese consumption. In the open-hearth 
process the bulk of manganese ferroalloy 
is added to the furnace during steelmak- 
ing, resulting in considerable manganese 
losses. With the basic oxygen converter 
the manganese ferroalloy can be added to 
the ladle at the same time as other ele- 
ments, improving the yield. The electric 
furnace can lower the unit consumption of 
manganese for a particular type of steel 
even more by further reducing the loss of 
manganese to slag through oxidation com- 
pared with the other processes. 

The unit consumption of manganese as 
ferroalloys per ton of raw steel produced 
in the United States in 1982 and 1983 was 
significantly below the levels of previ- 
ous years — the 1983 usage rate was about 
75 pet of that in 1981. Just a few years 
ago, such a dramatic reduction over such 
a relatively short period of time was 
considered impossible. Although product 
mix is a relevant factor, the change has 
happened principally because of the 
rapid adoption of new steelmaking prac- 
tices whose benefits include a decrease 
in manganese processing losses. Most 
steelmakers have ceased the original re- 
fining practice of blowing all the oxygen 
on the top of the bath. The initial de- 
parture from the basic oxygen process 
(BOP) was the Q-BOP or OBM process in 
which all the oxygen is blown through 
bottom tuyeres to provide more efficient 
mixing and thus achieve higher yields, 
greater cleanliness, and low carbon lev- 
els. A modified form, K-BOP, blows only 
40 pet of the total oxygen through the 
bottom, while the rest is top blown. 
Since the bottom-blown furnace has high 
capital requirements, several simpler 
processes requiring less capital have 
been developed by various steel compa- 
nies. They combine top blowing of oxygen 
and bottom stirring with inert gas. In 
some cases, bottom stirring is coupled 
with a small amount of bottom-blown oxy- 
gen. In addition to higher manganese 
residuals, these new technological devel- 
opments offer higher yields , less flux 
consumption, better aluminum recovery, 



37 



low carbon levels, increased scrap utili- 
zation, and better removal of impurities, 
at lower cost. 

It was previously thought that the only 
opportunities available to lower the spe- 
cific demand for manganese in steel would 
be evolutionary changes , such as — 

Electric furnace steelmaking, since a 
higher percentage of electric furnace 
production capacity would reduce manga- 
nese losses from oxidation compared with 
open-hearth and basic oxygen converter 
processes. 

External desulf urization , which uti- 
lizes calcium carbide or magnesium to 
lower the sulfur content of iron that is 
to be subsequently processed into steel. 

Argon-oxygen decarburization (AOD) , 
which allows better retention of easily 
oxidized materials such as manganese; 
extension of AOD to a wider range of al- 
loy and carbon steels would increase the 
efficiency of manganese utilization. 

Direct reduced iron (DRI) , since usage 
in steelmaking furnaces can lower manga- 
nese needs because of its low sulfur 
content. 

Continuous casting of raw steel , which 
increases the yield of steel products and 
lowers the amount of scrap that must be 
recycled, thus minimizing remelting (and 
attendant manganese loss) and increasing 
the overall efficiency of manganese uti- 
lization in the system. 

Packaging of manganese alloys , which 
avoids losses from abrasion and breakage 
of alloys during handling in the usual 
bulk form. 

Tighter specifications , since manganese 
content may be broader and higher than 
necessary to meet property requirements 
for some grades of steel. 

Whereas the recent decline of nearly 
25 pet in unit manganese consumption, 
attributable largely to new steelmaking 
technology, occurred in only 2 yr, full 
attainment of the manganese conservation 
potential of the alternatives listed 
above, although of similar magnitude (20 
to 30 pet) , is considered long term. 
Their conservation potential is probably 
in the range of 10 to 15 pet in the short 
term (several years). 



Most of the manganese that is lost from 
the steelmaking system goes to the slag. 
A portion of the slag is returned to the 
blast furnace, where some manganese is 
recovered in the pig iron. The propor- 
tion of slag that can be recycled is lim- 
ited by its phosphorus content because 
the phosphorus entering the blast furnace 
ends up in the pig iron and would build 
up excessively if sufficient slag were 
not discarded. Steelmaking slags are not 
a promising potential source for reclama- 
tion of manganese. The slags are low 
in manganese content (4.5 to 9 pet) and 
are not amenable to direct treatment by 
hydrometallurgical methods, instead re- 
quiring energy-intensive pyroraetallurgi- 
cal or combined pyrometallurgical-hydro- 
metallurgical processing. Also, existing 
slag dumps are usually intermixed with 
other refuse. 

Most manganese contained in steel scrap 
is oxidized and lost to slag when scrap 
is recycled in steelmaking furnaces. 

Nonferrous Alloys 

Manganese is used as a component of 
some nonferrous alloys to impart hard- 
ness, stiffness, and corrosion resist- 
ance. Aluminum alloys containing I pet 
or more manganese are used for bever- 
age cans and food handling equipment. 
Manganese bronzes (copper-base alloys 
strengthened by small additions of manga- 
nese) are found in marine propellers and 
fittings, gears, and bearings. High- 
manganese-content specialty alloys in- 
clude copper-manganese-nickel electrical- 
resistance alloys, which contain 10 pet 
or greater manganese, and alloys with 
high coefficients of thermal expansion 
for bimetallic elements of thermostats. 

Batterie s (62) 

Manganese dioxide has long been a com- 
ponent of the common dry-cell battery. 
Depending on costs and desired battery 
characteristics, the manganese dioxide 
that is used may be from certain natural 
ores, a synthetic form produced by elec- 
trolytic or chemical means, or a blend of 



38 



both materials. Manganese dioxide had 
been thought to act as a depolarizer by 
removing any hydrogen that formed, but 
according to current theory, it partici- 
pates directly in the electrochemical re- 
action of the cell. Substitution with 
alternative batteries is possible, but 
for economic reasons only to a limited 
extent. 

Chemicals and Miscellaneous 
(37, J37, 60, 62) 

Manganese ore is used as an oxidant in 
the production of hydroquinone, which has 
applications in photographic developers 
and in the production of certain types of 
rubber and plastic. Ore is also employed 
as a decolorizing agent to neutralize the 
iron content common in most glass sands. 

Potassium permanganate is a powerful 
oxidant frequently utilized in water 
treatment and purification, as well as a 
variety of other chemical applications. 
Manganese dioxide is used in the sealant 
of incandescent light bulb bases, and as 
part of the frits for bonding glass and 
porcelain to metal. Manganous oxide is 
utilized as an additive to livestock and 
poultry feeds, and as a component of 
welding rods and fluxes. Manganese sul- 
fate is used as a fertilizer supplement; 
manganese chloride as a textile dye and a 
magnesium alloy flux; and manganese per- 
sulfate as an oxidizing agent in the 
synthesis of organic compounds. Substi- 
tution is possible for some of the oxi- 
dant, chemical, and miscellaneous uses of 
manganese, but seldom where requirements 
call for the metal itself. 



SUPPLY ALTERNATIVES 
Domestic (56, 62 , 64 ) 

The Bureau of Mines investigated the 
availability of manganese from eight 
known domestic occurrences (table 13). 
These deposits were found to have demon- 
strated resources totaling 420 million 
mt , but with an average grade of only 
10 pet contained manganese. Principally 
because of high benef iciation and trans- 
portation costs, prices substantially in 
excess of those currently prevailing in 
the market would be required for develop- 
ment, in the absence of a major cost- 
reducing technological breakthrough. Al- 
though annual production of domestic ore 
could theoretically reach a maximum of 
900,000 mt of recoverable manganese, the 
lag time in bringing these individual 
sites on-stream would range from 3 to 
6 yr. 

Since manganese can be moved and con- 
centrated readily in a number of geologic 
environments, many undiscovered concen- 
trations may exist. However, its lack of 
a distinctive geophysical expression and 
its abundance in subeconomic concentra- 
tions hinder standard geophysical and 
geochemical exploration techniques. On 
the basis of geologic inference, it has 
been suggested that the possibility of 
sizable, high-grade, U.S. deposits is 
greatest in the Atlantic and Gulf Coastal 
Plains and in the North Central States, 
but the level of understanding of ore 
formation is inadequate to predict a suf- 
ficiently small region of high potential. 



TABLE 13. - Domestic manganese resources 



Mine 



•tate 


Ore grade, 


Demonstrated 




pet 


resources, 10 3 mt 


AZ 


15.0 


5,895.5 


AZ 


8.75 


8,441 


CO 


10.0 


24,909 


ME 


8.87 


260,000 


ME 


9.54 


63,100 


MN 


7.84 


48,960 


MT 


18.0 


1,232 


NV 


13.2 


7,230 



Hardshell Mine 

Maggie Mine 

Sunnyside Mine 

Maple Mountain-Hovey Mountain. . 
North Aroostook District (Dud- 
ley and Gelot Hill) 

Cuyuna North Range (SW portion) 

Butte District (Emma Mine) 

Three Kids Mine 



39 



Foreign (56-57, bl, 65-66) 

There is no shortage of manganese 
worldwide — adequate reserves exist to 
meet foreseeable needs, but they occur 
primarily in the Republic of South Africa 
and the U.S.S.R. These nations are cur- 
rently the two largest producers of man- 
ganese ore. Although much of its produc- 
tion is considered submarginal by market 
economy standards, the U.S.S.R. prefers 
to meet its manganese requirements inter- 
nally and provides most of the manganese 
consumed by the other centrally planned 
economy countries as well. However, 
these countries have been increasing 
their imports of manganese from non- 
Soviet sources. In the future, market 
economy countries will likely continue to 
depend on a few suppliers for most of 
their manganese ore. The prominence of 
the Republic of South Africa is expected 
to increase because of its resource posi- 
tion and relatively cheap energy. Gabon, 
whose metallurgical-grade ore is among 
the richest in the world, will be able to 
increase output by nearly 50 pet when the 
Trans-Gabon Railroad is completed. Aus- 
tralia should also continue as a leading 
ore producer and export. Brazil's prin- 
cipal mine, Serra do Navio, will be de- 
pleted of reserves in the next decade, 
and while deposits in the Carajas region 
promise to fill the void, ore exports 
from that source are expected to be lim- 
ited in favor of conversion to manganese 
ferroalloys for export and captive use. 
India's role as a major ore supplier 
could diminish somewhat because of inter- 
nal needs, depending on developments in 
the Indian steel and ferroalloy indus- 
tries. While presently a moderate-scale 
world producer of relatively low-grade 
carbonate ore, Mexico has sufficient de- 
posits to support a substantial increase 
in production. Mexico thus appears to 
offer an opportunity for a secure, acces- 
sible, alternative source of manganese 
for the United States, although the ore 
requires roasting and blending with 
higher grade material. 

As with chromium, primary raw material 
supplies, i.e., manganese ore, may no 



longer be the main concern for the United 
States, because imports of manganese are 
increasingly in the form of ferroalloy. 
There is a clear and accelerating trend 
to convert ore to manganese ferroalloys 
by the ore-producing countries at the 
expense of production capacity in the 
United States. Of the major ore pro- 
ducers, only Gabon has no ferroalloy 
capacity as yet. Without adequate or 
alternative U.S. manganese ferroalloy 
capacity, the issue of a secure source of 
manganese has a different connotation. 
The major world producers of manganese 
ferroalloys are the U.S.S.R., Japan, 
China, the Republic of South Africa, Nor- 
way, and France. 

Ocean M inera ls (56) 

Typical deep-sea nodules contain 25 to 
35 pet Mn on a dry basis, and the re- 
source potential of marine manganese 
crusts is currently being assessed. Pre- 
vious discussion has touched on the pres- 
ent impediments to ocean mining. 

Stockpile (62) 

Provided that the National Defense 
Stockpile materials are satisfactory for 
their intended purposes, quantities of 
chemical- and battery-grade manganese in 
inventory were in excess of stockpile 
goals, except for synthetic manganese 
dioxide. The inventory of metallurgical 
ore stood at 89 pet of the goal as of 
November 30, 1983, but the shortfall 
could be more than met by offset credits 
from inventories of ferroalloys and metal 
in excess of goals. 

In December 1982, it was announced that 
a portion of stockpiled manganese ore 
would be upgraded into high-carbon ferro- 
manganese as part of a program to Im- 
prove stockpile readiness and to maintain 
some domestic ferroalloy capacity. The 
plan called for the production of about 
577,000 st of f erromanganese over a 10-yr 
period. In 1983 and 1984, GSA contracted 
for upgrading a total of approximately 
128,000 st of ore. 



40 



SUMMARY OF DEMAND AND SUPPLY ALTERNATIVES 

The bulk of manganese consumed in the 
United States (about 90 pet) is used 
for its desulf urizing, deoxidizing, and 
alloying functions in ironmaking and 
steelmaking. 

The universal use of manganese in 
steelmaking results from its abundant 
supply and its low cost relative to 
that of other materials and of modified 
steelmaking practices that might accom- 
plish the same ends. From a practical 
standpoint there is no substitute for 
manganese. 

The phasing out of open-hearth steel- 
making has resulted in a corresponding 
decline in unit manganese consumption. 
Both the basic oxygen converter and the 
electric furnace result in improved 
yields of manganese. 

The adoption of new steelmaking prac- 
tices that combine top blowing of oxygen 
and bottom stirring with inert gas has 
been a major factor in reducing the unit 
consumption of manganese as ferroalloys 
per ton of raw steel produced by nearly 
25 pet in only 2 yr. 

Other technological opportunities capa- 
ble of lowering the specific demand for 
manganese per ton of steel are evolution- 
ary changes, not breakthroughs. Full at- 
tainment of the manganese conservation 
potential of these alternatives could re- 
duce the unit manganese consumption by 
20 to 30 pet. In the short run (several 



years) their conservation potential is 
probably in the range of 10 to 15 pet. 

Most of the manganese that is lost from 
the steelmaking system goes into the 
slag, but the proportion of slag that can 
be recycled is limited by its phosphorus 
content. Steelmaking slags are also not 
a promising potential source for economi- 
cal reclamation of manganese because of 
their low manganese content and lack of 
amenability to direct hydrometallurgical 
treatment methods. 

The quantity of manganese used in the 
United States for purposes other than 
ironmaking and steelmaking (nonferrous 
alloys, batteries, chemicals) amounts to 
only about 10 pet of demand. 

Domestic manganese deposits contain 
low-grade ore and would require market 
prices substantially in excess of those 
currently prevailing to warrant develop- 
ment. Bringing the individual sites on- 
stream would require from 3 to 6 yr. 

Mexico appears to offer an opportunity 
for a secure, accessible, alternative 
source of manganese ore for the United 
States. 

There is an accelerating trend to con- 
vert manganese ore to manganese ferro- 
alloys by the ore-producing countries, 
at the expense of production capacity in 
the United States and other consuming 
nations. U.S. imports of manganese fer- 
roalloys now substantially exceed those 
of manganese ore. 



PLATINUM-GROUP METALS 



BACKGROUND 

The platinum-group metals consist of 
platinum, palladium, iridium, osmium, 
rhodium, and ruthenium. They exhibit 
several remarkable properties including 
resistance to corrosion and oxidation 
even at high temperatures; extensive and 
sometimes unique catalytic activity; high 
melting points; and great strength. As 
a result, they are used as automotive, 
chemical process, and petroleum refining 
catalysts, and in electrical devices, 
dental supplies, jewelry, and glass manu- 
facturing. Of the six metals compris- 
ing the group, palladium and platinum 



together account for approximately 90 pet 
of consumption (table 14). In spite of 
the high initial cost, platinum-group 
metals continue to be used because they 
are generally superior to other less ex- 
pensive or more widely available materi- 
als, and in nondissipative uses, they ex- 
hibit excellent recyclability (table 15). 
A very small quantity of platinum-group 
metals is derived from domestic copper 
mining as a byproduct. About 10 pet of 
the annual supply consists of recycled 
metal. The remainder is imported, mostly 
as refined metal from the Republic 
of South Africa, the U.S.S.R., and the 
United Kingdom. The latter refines some 



41 



TABLE 14. - Platinum-group metals sold' to consuming industries 
in the United States 

(Thousand troy ounces) 



Use 


Pt 


Pd 


Ir 


Os 


Rh 


Ru 


Total 3 




Quantity 


pet 


1981 
Catalysts: 


447 
88 

78 
112 
29 
28 
19 
72 


129 
21 
90 

345 

3 

15 

255 
30 


( 2 ) 

2 

1 

4 



1 
( 2 ) 

1 




( 2 ) 




( 2 ) 




30 



9 
12 

4 

4 

( 2 ) 
4 


1 

( 2 ) 

52 

27 



1 

( 2 ) 

6 


607 
111 
231 
500 
36 
47 
275 
114 


32 




6 




12 




26 




2 




2 




14 
6 




873 


889 


8 


1 


62 


88 


1,921 


100 


1982 
Catalysts : 


478 
22 
64 
90 
21 
16 
23 
68 


118 

21 

129 

312 

( 2 ) 

8 

311 

27 


( 2 ) 

1 

1 

5 
( 2 ) 

1 
( 2 ) 

2 





( 2 ) 





1 




26 

( 2 ) 

7 

9 

2 

3 
( 2 ) 

2 






64 

21 



( 2 ) 

( 2 ) 

20 


623 

43 

264 

438 

23 

29 

335 

118 


33 




2 




14 




23 




1 




2 




18 
6 


Total 3 


780 


926 


11 


1 


50 


105 


1,873 


100 






1983 
Catalysts: 


508 
38 
65 
75 
15 
10 
17 
68 


172 
50 
40 

250 

( 2 ) 
7 

344 
60 


( 2 ) 

1 

1 

1 
( 2 ) 

1 
( 2 ) 

1 





( 2 ) 





1 




20 



4 

8 

2 

2 
( 2 ) 

8 




( 2 ) 

55 

71 



1 

( 2 ) 

17 


700 

89 

165 

406 

17 

21 

362 

154 


37 




5 




9 




21 




1 




1 




19 
8 


Total 3 


797 


922 


5 


1 


44 


145 


1,914 


100 







Primary and non- 
2 Less than 1/2 un 
3 Data may not add 



toll-refined secondary metals. 
it. 
to totals shown because of independent rounding. 



TABLE 15. - Secondary platinum-group metals toll-refined in the United States 

(Thousand troy ounces) 





Metal 


1981 


1982 


1983 


Metal 


1981 


1982 


1983 


Pt 


521 

607 

8 

2 


394 
431 

10 
1 


434 

457 

6 

1 


Rh 


35 
18 


27 
6 


42 






56 


Ir 


Total ' 


1,191 


868 


995 









Data may not add to totals shown because of independent rounding, 



42 



South African and Canadian material, 
but world mine production of platinum- 
group metals is virtually the exclusive 
domain of the U.S.S.R. and the Republic 
of South Africa. Recent U.S. net import 
reliance has been 80 pet or more of ap- 
parent consumption. 

The consumption of all platinum-group 
metals totaled 1.914 million tr oz in 
1983; the highest level of platinum-group 
metal consumption was 2.756 million tr oz 
in 1979. Producer and dealer prices in 
1983 were $475/tr oz and $424/tr oz 
respectively for platinum, and $130/tr oz 
and $136/tr oz respectively for 
palladium. 

The U.S. demand for platinum-group met- 
als collectively is expected to grow at 
an average annual rate of 2.9 pet from 
1981 to the year 2000. Table 16 contains 
world production of platinum-group met- 
als, world reserves, and imports by the 
United States. 

USES AND DEMAND ALTERNATIVES 

Catalysts 

Automotive Emission Control (67-71) 

The most significant event affecting 
the consumption of platinum-group metals 
in the United States has been their adop- 
tion as catalysts for the control of auto 
exhaust emissions. From 1965 through 
1974 the automotive industry was able to 
comply with exhaust emission standards by 
engine modifications, but to the detri- 
ment of fuel economy and performance. 
Additional reductions in emissions man- 
dated by more restrictive standards led 
to the incorporation of catalytic con- 
verters in the exhaust system, which 
allowed the engine to operate with more 
effective ignition timing, thereby im- 
proving economy and performance. Thus, 
the automotive industry became the single 
largest consumer of platinum in the 
United States (while the petroleum indus- 
try also had to increase its use of plat- 
inum catalysts for the production of 
lead-free gasoline required by auto- 
mobiles equipped with converters). Al- 
though many potential catalyst materials 



have been examined since the late 1960's, 
to date only platinum-group metals, cur- 
rently combinations of platinum, palladi- 
um, and rhodium (average loading ratio 
10.3:3.9:1), have shown the necessary ef- 
ficiency and durability. The possibility 
that a suitable base-metal catalyst may 
be developed cannot be discounted, but 
this would constitute a breakthrough and 
therefore cannot be predicted to occur at 
any particular point in time. 

Although the metal is virtually intact 
at the end of a converter's useful life, 
reclamation of platinum-group metals from 
catalytic converters presents a complex 
problem. The combination of low concen- 
trations of precious metals (averaging 
0.079 tr oz per unit) and difficulties in 
converter collection presents technical 
and logistical challenges. The total 
amount of precious metals involved is 
significant — about 6.5 million tr oz of 
platinum-group metals have been sold to 
the U.S. automotive industry from 1974 
through 1983. Approximately 80 pet of 
the amount is still contained on operat- 
ing vehicles, but only 15 to 20 pet of 
the remainder has been recycled. Com- 
plete recycling of all platinum-group 
metals does not occur because a portion 
is lost during normal life; not all is 
recoverable by refiners, especially if 
the catalyst is contaminated; and many 
converters are lost to scrap shredders or 
are being held by speculators. At pres- 
ent, costs are high, the market is specu- 
lative, and supply is erratic, but as 
industry awareness and the efficiency 
of the collection chain (dismantlers, 
collectors, decanners, and refiners) im- 
prove, recycling should increase. By 
1988, an estimated 8.5 million cars per 
year will be scrapped. One estimate of 
the extent of platinum-group metal recov- 
ery that is possible projects a 70-pct 
rate ( 70 ) . Short-term solutions to a 
lack of platinum-group metal availabil- 
ity, such as a relaxation of emission 
standards whereby non-precious-metal cat- 
alysts could achieve a reduced emission 
standard or a moratorium on the use of 
converters, obviously compromise the 
quality of the environment. 



43 



TABLE 16. - World platinum-group metal production, reserves, and U.S. imports 

(Thousand troy ounces) 



Country 



Australia 

Belgium-Luxembourg 

Canada 

China 

Colombia 

Costa Rica 

Ethiopia 

Finland 

Germany, Federal Republic of 

Hong Kong 

Italy 

Japan 

Korea, Republic of 

Mexico 

Netherlands 

No rway 

Panama 

Peru 

Singapore 

South Africa, Republic 

Spain 

Sweden 

Switzerland 

Taiwan 

U.S.S.R 



.c of 



United Kingdom. 
United States . , 

Venezuela , 

Yugoslavia. 

Zimbabwe , 

Other 

Total 4 , 



Production 



1981 1982 p 



15 



383 



15 


( 2 ) 
4 



3 36 








3,110 





3,350 

7 

4 
8 




6,931 



14 



228 



20 



( 2 ) 
9 



3 43 








2,600 





3,500 

8 

3 
4 




6,431 



1983' 



14 



167 



20 



( 2 ) 

9 







3 59 















2,600 





3,600 

6 

3 
4 




'Less than 1 million tr oz 

^Recovered from imported 

totals shown because of in 



6,482 



Reserves 



NA 



8,000 

NA 
(') 



NA 

NA 











790,000 




190,000 

1,000 


NA 

(') 

NA 



1,000,000 



U.S. imports 



1981 



26 
140 

78 

4 

10 

3 

19 

53 
3 
1 


79 

42 

33 
6 

11 



621 

9 

6 

37 

359 
303 




7 



2,850 



1982 



5 
107 

95 

1 
3 

6 

31 


28 

4 



162 

27 

27 

1 

1,195 
2 

5 
35 



405 

339 









18 



2,494 



1983 



20 

208 

231 

7 

7 

4 



3 

83 

1 

54 

10 

1 

78 

35 

17 





5 

1,219 

6 

23 

61 

58 

430 

639 



15 



1 

2 



3,218 



NA Not available. 
2 Less than 1/2 unit. 
4 Data may not add to 
5 Rounded. 



ore. 
dependent rounding, 



Ceramics present an opportunity for 
heat engines to operate at temperatures 
beyond those attainable by current metal- 
lic engines. This capability translates 
into enhanced systems performance in the 
form of greater fuel economy and substan- 
tially reduced emissions. Should ce- 
ramics become the material of the future 
generation of heat engines, there would 
be a major reduction in the amount of 



platinum-group metals required to control 
automotive emissions (28). 

Petroleum Refining (67) 

The use of platinum-group metals in 
petroleum refining occurs mostly in hy- 
drocarbon reforming with conventional 
(platinum) or bimetallic (platinum and 
rhenium or iridium) catalysts. Other 



44 



refining processes (hydrocracking, iso- 
merization, hydrotreating) are relatively 
minor uses for platinum and palladium, 
and the processes rely only partially on 
these metals for catalysts. 

The substitution of other materials, 
such as molybdenum, for platinum in re- 
forming catalysts would reduce the ef- 
ficiency of the process. Fortunately, 
there is a large inventory of platinum- 
group metals in place. The catalysts 
are recycled on a toll-refined basis, re- 
turned as sponge, and remanuf actured into 
new catalysts. The loss rate is very low 
(97 pet of the metal in spent refining 
catalyst is reclaimed) , which would en- 
able the petroleum refining industry to 
continue to operate without the constant 
need for new metal. 

Chemical Processing {bl_, 72-74) 

The oxidation of ammonia to nitric acid 
is the major chemical process employing 
platinum-group metal catalysts. Nitric 
acid is an intermediate in the synthesis 
of ammonium nitrate (fertilizer, explo- 
sives) and is used as a reactant or pro- 
cess chemical in the production of adipic 
acid (nylon fibers, plastics) and in the 
synthesis of intermediates which are fur- 
ther processed into compounds such as 
aniline (rubber, dyes, pharmaceuticals, 
pesticides) and diisocyanates (polyure- 
thane foams, plastics, elastomers). Ni- 
tric acid is also used directly for 
stainless steel pickling. The catalyst 
consists of a platinum wire woven into a 
fine mesh gauze with about 10 pet Rh 
added to increase strength and efficiency 
and reduce catalyst losses. Typically a 
"pack" of 20 gauzes is utilized. Some 
on-site regeneration of the catalysts can 
be performed, and metal losses can be re- 
covered (55 to 70 pet) with catchment 
gauzes and mechanical filters, but after 
losing a certain percentage of its ini- 
tial weight, the catalyst is replaced and 
recycled. An alternative, cobalt oxide 
with additions of other metal oxides, is 
available at lower cost, but certain as- 
pects of its performance are inferior. 
It appears unlikely that platinum gauze 
will be superseded by this base metal 
catalyst. 



Noble metal catalysts are broadly used 
elsewhere in the chemical and pharmaceu- 
tical industries, but their use in large- 
scale processes such as organic oxidation 
(acetaldehyde , acetone, acetic anhydride, 
acetic acid, vinyl acetate, oxo alco- 
hols), hydrocarbon alkylation and isomer- 
ization, and hydrogenation is relatively 
recent. Often platinum-group metals are 
not the primary catalysts but rather are 
used in selective applications. As with 
petroleum refining catalysts, the recy- 
clability of platinum-group metals uti- 
lized as chemical process catalysts is 
high — about 85 pet. 

Electrical and Electronic (67) 

These applications depend on the chemi- 
cal inertness and thermal stability of 
platinum-group metals and are probably 
more numerous, involve more product 
forms, and utilize a wider range of alloy 
compositions than any other industry. As 
expected, home scrap and prompt indus- 
trial scrap are recycled to a far greater 
extent than obsolete scrap, although the 
Department of Defense operates a program 
to recover platinum-group and other pre- 
cious metals from surplus, outdated, and 
damaged Government items. 

Contacts 

Low-voltage, low-energy contacts, such 
as found in telephone switching equipment 
and relays require materials that provide 
low and stable contact resistance in var- 
ious environments for as long as 40 yr by 
exhibiting minimal corrosion and wear. 
Platinum-group metals, especially palla- 
dium, have been used extensively since 
the lower cost of palladium offsets the 
generally superior performance of gold. 
However, replacement of electromechanical 
devices with electronic switching systems 
is displacing platinum-group metals from 
this sector. 

Certain contacts (relays, voltage regu- 
lators, thermostats, switches, slip-ring 
assemblies) operate at higher voltages 
and contact forces and may require better 
wear and arc erosion resistance. Medium- 
to heavy-duty relays and switches use 
platinum alloyed with 5 to 14 pet Ru. 



45 



Palladium-silver alloys also are used in 
this way. For slip-ring assemblies com- 
plex platinum-group metal alloys are used 
as well as electrodeposited rhodium. 

Thin- and Thick-Film Circuits 

In thin-film circuits and some sili- 
con integrated circuitry, thin layers of 
platinum or palladium are applied by 
sputtering or evaporation to provide re- 
liable conductor adhesion. In thick-film 
and hybrid-integrated circuits, composi- 
tions of gold and platinum or palladium, 
or of palladium and silver, applied as 
screened-on pastes are used for conduc- 
tors. Ruthenium applied as a ruthenate 
paste and converted to ruthenium oxide 
is used as a resistor material on these 
circuits. Platinum-group metal use in 
thick-film and hybrid integrated circuits 
may be challenged by copper pastes. 

Thermocouples and Furnace Components 

Various combinations of platinum, rho- 
dium, and iridium are utilized in typi- 
cal high-temperature thermocouple sys- 
tems. Ultrapure platinum is used as a 
resistance thermometer; platinum with 10 
to 40 pet Rh is used for windings in fur- 
naces operating to 1,800° C in air; un- 
alloyed platinum and rhodium are used for 
heater windings. 

Electrodes and Miscellaneous 

Multilayer ceramic capacitors are a 
rapidly growing end use for palladium in 
the form of silver-palladium alloy elec- 
trodes. However, lower cost nickel and 
lead alternatives are being evaluated. 

Ruthenium oxide is used as a coating on 
dimensionally stable titanium anodes used 
in the production of chlorine and caustic 
soda. Platinum and platinum-palladium 
alloys are used as insoluble anodes for 
the cathodic protection of ships and 
pipelines. Materials for spark plug 
electrodes include platinum with 4 pet W, 
platinum-rhodium alloys, and iridium (es- 
pecially in heavy-duty aircraft engine 
spark plugs). Fine platinura-iridium wire 
is used as fuse wire for explosive 
detonators . 



Glass (67 , 75_) 

Platinum and platinum-rhodium alloys 
are used in a wide variety of glass han- 
dling and forming equipment because of 
their high melting point, hot strength, 
low oxidation rate, good corrosion re- 
sistance, and noncontaminating nature. 
Pure platinum is used for glass melting 
tanks, stirrers, and crucibles for melt- 
ing high-quality optical and special 
glasses. Platinum with 10 pet Rh is used 
for the bushings and baskets needed in 
the production of glass fibers. Platinum 
with 40 pet Rh is used for crucible 
liners, structures for conveying mol- 
ten glass, fiber-optics-forming devices, 
laser-glass melters, and stirrers for 
glass horaogenization. Iridium is used as 
an extrusion die material for glasses of 
high melting points. 

Very low metal losses (about 2 to 4 
pet) are experienced in these uses. Worn 
parts are recycled on a toll basis and 
returned to the industry for fabrication 
into new parts. 

Jewelry (67) 

Platinum-group metal alloys, commonly 
platinum with 10 pet Ir , platinum with 5 
pet Ru , platinum with 4 pet Pd , and pal- 
ladium with 5 pet Ru , are used for jew- 
elry in cast and wrought form for maximum 
prestige, reliability, and gem retention. 
Rhodium as a thin electrodeposit is often 
used over these or silver jewelry to pro- 
vide added whiteness, wear resistance, 
and immunity to tarnishing. In addition, 
a variety of platinum-group metal-con- 
taining inks and pastes are used for 
decoration of china, glass, and ceramics. 

Jewelry certainly seems to be an end 
use that could be easily dispensed 
with, should the availability of plat- 
inum-group metals become limited. Ironi- 
cally, however, Japanese consumption of 
platinum for jewelry, which has almost 
singlehandedly made jewelry the world's 
largest end use for the metal, has 
made large quantities of its copruducts 
available . 



46 



Dental and Medical (67) 

Platinum, palladium, and a variety of 
complex gold-silver-copper alloys that 
contain these elements find wide use 
as dental restorative materials and bone 
prosthetic treatments. Palladium is 
emerging as the precious metal of choice, 
replacing gold, platinum, and platinum- 
iridium alloys because it provides suffi- 
cient strength at lower cost. Primary 
medical uses of platinum-group metals 
include platinum coordination compounds 
used in cancer chemotherapy and platinum- 
iridium alloy body implant probes, elec- 
trodes, and needle tubing. 

Mis cellaneous (67) 

Laboratory Apparatus 

Because of its resistance to high tem- 
peratures and chemical attack, platinum 
has found many uses in chemical labora- 
tories, including crucibles or boats made 
from platinum hardened with rhodium for 
fusions or combustions, electrodes of 
platinum hardened with iridium for elec- 
trolytic methods and electrodepositions , 
thermocouples, thermistors, instrument 
components, and research compounds. 

Crystal Growth 

Platinum, platinum alloys with rhodium 
or iridium, and iridium find use as cru- 
cible materials in the flux and melt 
growth of single crystals of oxide com- 
pounds that melt at high temperatures. 
These include sapphire for semiconductor 
substrates, gadolinium-gallium-garnet for 
bubble memory devices, neodymium-doped 
yttrium-aluminum-garnet and ruby for op- 
tically pumped lasers, synthetic gem- 
stones, and lithium columbate and lith- 
ium tantalate modulator and transducer 
materials. 



a few thousand troy ounces annually and 
accounts for less than 1 pet of domestic 
consumption. The Bureau of Mines inves- 
tigated the availability of platinum 
(only) from domestic sources (table 17) 
and concluded that only one deposit, the 
Salmon River (Goodnews Bay Mine) , was 
capable of producing platinum at $420/ 
tr oz, the January 1980 producer price. 
This mine has been the largest producer 
of primary platinum in the United States, 
totaling 641,000 tr oz , and it has been 
estimated that the deposit could yield 
an additional 500,000 tr oz at a rate of 
10,000 tr oz/yr. Production ceased after 
1975 but resumed on a limited basis from 
1980 to 1982. The Salt Chuck deposit in 
Alaska has also been an intermittent pro- 
ducer of platinum-group metals, but total 
mineralized material and demonstrated re- 
sources are quite limited. 

In 1983, the three companies involved 
in the exploration of the Stillwater Com- 
plex in Montana formed a new three-way 
partnership to further evaluate the de- 
posit. Factors that have held back the 
development of the Stillwater Complex in- 
clude environmental concerns for the sur- 
rounding wilderness area, locations of 
tailings disposal sites, remoteness and 
climate of the site, and fluctuations in 
platinum-group metal demand and prices. 
The companies involved with the deposits 
in the Duluth Gabbro in Minnesota have 
ceased exploration activity there. The 
relative mix of platinum-group metals in 
both the Stillwater Complex and the Du- 
luth Gabbro greatly favors palladium over 
platinum (78 versus 18 to 20 pet), which 
does not correspond well to industrial 
demand. 

The total amount of recoverable plati- 
num potentially available from the U.S. 
deposits analyzed in the Bureau study 

TABLE 17. - Total U.S. platinum 
resources 1 



SUPPLY ALTERNATIVES 

Domestic (67, 76-77) 

Platinum and palladium are recovered in 
the United States as byproducts of copper 
refining, but this production totals only 



(Million troy ounces) 

Contained 3 

Recoverable 2 

includes Salmon River, AK; Ely Spruce, 
MN; Minnamax, MN; Stillwater, MT; Ana- 
conda, MT. 



47 



is about 2.3 million tr oz . At assumed 
production capacities, these deposits 
are capable of producing only 113,000 
tr oz annually — less than 15 pet of U.S. 
requirements. 

Foreign (67 , 76-_77) 

Nearly all of the world's reserves of 
platinum-group metals are in the Republic 
of South Africa and the U.S.S.R. The 
grade of the South African deposits en- 
ables platinum-group metals to be mined 
as the principal product, unlike most 
other occurrences. Canada, the third- 
largest producer, presents a nearby, se- 
cure source of supply, but platinum-group 
metal production is limited by its sta- 
tus as a byproduct of copper and nickel. 
Likewise, Australian output is also rele- 
gated to a byproduct role. Although pro- 
duction in Colombia occurs as a coproduct 
of gold and silver, production facil- 
ities there are aging. Platinum-group 
metal deposits in Brazil are not under 
development . 

At present the entire platinum-group 
metal output of these alternative (to 
the Republic of South Africa and the 
U.S.S.R.) countries represents only about 
20 pet of U.S. primary demand. It ap- 
pears that the Republic of South Africa 
is assured of continuing as the major 
supplier of platinum-group metals to the 
United States. 

Stockpile ( 67 , 77) 

Only three of the platinum-group met- 
als — platinum, palladium, and iridium-- 
are held in the National Defense Stock- 
pile. The inventories of each, however, 
are considerably below their goals: 
platinum, 34 pet; palladium, 42 pet; iri- 
dium, 26 pet. Since 1982 GSA has pur- 
chased a total of 10,900 tr oz of iridium 
from the stockpile. Strictly speaking, 
none of the previous stockpile inven- 
tories of platinum-group metals meets 
both the current chemical requirements 
for purity and physical requirements for 
form, since the inventory is in bar, 
plate, or sheet form, in contrast to more 
recent specifications of metallic sponge, 



and the purity levels of a portion of the 
stockpile preclude consumption in the 
highest purity applications. 

SUMMARY OF DEMAND AND SUPPLY ALTERNATIVES 

Although many potential auto emission 
catalyst materials have been examined, 
only platinum-group metals have shown 
the necessary efficiency and durability. 
The development of a suitable base metal 
catalyst would constitute an unforesee- 
able breakthrough. 

The combination of low concentrations 
of precious metals and difficulties in 
converter collection presents technical 
and logistical challenges to automotive 
catalyst reclamation. However, it is es- 
timated that a 70-pct metal recovery rate 
could be achieved. 

A relaxation of auto emission stan- 
dards, or a moratorium on the use of cat- 
alytic converters, could accomplish con- 
siderable conservation of platinum-group 
metals in a short time, but such action 
would comprise environmental quality. 

Platinum petroleum-refining catalysts 
are highly recyclable. Substitute cat- 
alysts such as molybdenum reduce process 
efficiency . 

Nitric acid manufacture is the major 
chemical process employing platinum-group 
metal catalysts. Some on-site catalyst 
regeneration can be performed, and recy- 
clability is very good. A lower cost co- 
balt oxide alternative is available, but 
certain performance aspects are inferior. 

Electrical and electronic applications 
of platinum-group metals are probably 
more numerous, involve more product 
forms, and utilize a wider range of alloy 
compositions than any other industry. 
Electronic switching systems, printed 
circuits, and metals such as gold, sil- 
ver, and tin-lead alloys offer alterna- 
tives in many applications. 

Platinum-group metals are utilized in a 
variety of glass handling and forming 
equipment, but very low metal losses are 
experienced in these uses; worn parts are 
recycled on a toll-refined basis. 

Gold and silver could readily substi- 
tute for platinum in jewelry uses. 



48 



Many dental and medical applications 
now using palladium could revert to the 
traditional material, gold, albeit at 
much higher cost. 

Regardless of price, at assumed pro- 
duction capacities, the combined plat- 
inum deposits in the United States could 
produce less than 15 pet of annual 
requirements . 



Nearly all of the world's platinum- 
group metal reserves are in the Republic 
of South Africa and the U.S.S.R. The 
Republic of South Africa seems assured 
of continuing as the major supplier of 
platinum-group metals to the United 
States. 



CONCLUSIONS 



COBALT 



Domestic Supply 



Current essential cobalt needs are 
estimated at about 50 pet of present 
consumption. 

Substitution 

Superalloys . - Significant amounts of 
cobalt could be replaced, but costly and 
time-consuming alloy optimization and 
engine certification programs would be 
required. 

Magnetic alloys . - An estimated 20 pet 
of current cobalt use is deemed 
essential. 

Cemented carbides. - Cobalt-free mate- 
rials cannot be considered as practical 
general alternatives. 

Wear-resistant alloys . - Where cobalt 
is required, lower cobalt substitutes 
will suffice. 

Tool and maraging steels. - Cobalt-free 
grades have been developed. 

Catalysts . - Hydrotreating is amenable 
to substitution. 

Paint drier s. - Elimination or reduc- 
tion of cobalt would incur substantial 
penalties in convenience and product 
quality. 

Other chemicals . - A 60-pct reduction 
in cobalt use could be accomplished. 

Processing 

Near-net-shape processes can achieve 
improved yields of usable product. 

Recycling 

Most in-house and prompt industrial 
scrap is recycled, and cobalt is gener- 
ally recovered; obsolete, low-grade, and 
mixed alloy scrap is not efficiently 
recycled. 



Development of domestic deposits would 
require a cobalt price of $20/lb to $25/ 
lb and could take 5 yr. 

Foreign Supply 

The most competitive cobalt resources 
in North America are the nickel deposits 
of Canada. 

CHROMIUM 

Current U.S. chromium consumption could 
be reduced by approximately one-third us- 
ing available technology. 

Substitution 



Stainless steels . - Chromium savings 
can be accomplished by partial replace- 
ment of the chromium in excess of 12 pet 
with other alloying elements, by com- 
pletely replacing stainless steel with a 
different metallic or nonmetallic materi- 
al, by employing thinner gauge or longer 
lasting high-chromium alloys, or by using 
surface modification techniques such as 
cladding, plating, and coating. 

Alloy steels . - Chromium content can be 
eliminated or reduced by using other 
alloying elements that also influence 
hardenability. 

Tool steels . - Substitution with sin- 
tered carbides entails serious cost 
penalties. 

Alloy cast irons . - Low- or no-chromium 
alternatives are available for roll, 
abrasion-resistant, and engineering 
types. 

Superalloys . - A high chromium content 
is essential only at the surface, not for 
mechanical properties. 



49 



Other alloys . - Substitutes for chro- 
mium are readily available in alloys of 
aluminum, titanium, and copper. 

Pigments and paints. - Replacement of 
chromium with proven alternatives would 
incur a substantial cost penalty or limit 
the number of available colors. 

Leather tanning. - No practical substi- 
tutes exist. 

Metal finishing and treatment.- Decora- 
tive electroplating could be replaced by 
chromium-free materials such as plastics, 
or by painting the substrate; electroless 
nickel provides an alternative to hard 
plating. 

Drilling mud additives. - No satisfac- 
tory substitutes exist for deep wells. 

Water treatment compounds . - No chro- 
mium-free corrosion inhibitors have been 
proven satisfactory at temperatures of 
150° F or higher; alternatives are avail- 
able for less critical applications. 

Wood treatment. - Nonchromium wood pre- 
servatives are readily available but do 
not offer comparable paintability . 

Processing 

Wider application of duplex refining 
systems for steel production appears to 
be a promising process area for achieving 
substantial conservation of chromium. 

Powder metallurgy techniques, such as 
rapid solidification and near-net-shape, 
offer possibilities for chromium conser- 
vation by producing unique properties via 
alloy microstructure and by generating 
less scrap. 

The continuing decline in open- 
hearth furnace steelmaking has dimin- 
ished the importance of chrome-bearing 
refractories. 

Recycling 

Stainless steel scrap is the major 
source of secondary chromium supply. 
Collection and processing costs hinder 
large-scale recovery from other metallur- 
gical industry processes. 



Domestic Supply 

No domestic chromite deposits are con- 
sidered suitable for development with 
existing technology at current market 
prices. 

Foreign Supply 

The known chromite resources of the 
Republic of South Africa and Zimbabwe 
are so vast that eventual concentration 
of supply there is expected. With the 
trend toward conversion of chromite to 
f errochromium in the ore-producing coun- 
tries, it is probable that future world 
f errochromium production will also be- 
come highly concentrated in these two 
countries . 

MANGANESE 

Substitution 



From a practical standpoint there is no 
substitute for manganese in steelmaking. 

Processing 

The recent adoption of new steelmaking 
practices that combine top blowing of 
oxygen and bottom stirring with inert gas 
has been a major factor in reducing the 
unit consumption of manganese. 

Full attainment of other technological 
opportunities could eventually reduce the 
unit manganese consumption by 20 to 30 
pet (in the short run 10 to 15 pet). 

Recycling 

The recyclability of steelmaking slag 
is limited by its phosphorus content. 
Slags are also not a promising potential 
source for economical reclamation of man- 
ganese because of their low manganese 
content and lack of amenability to direct 
hydrometallurgical treatment methods. 



50 



Domestic Supply 

Domestic manganese deposits contain 
low-grade ore and would require mar- 
ket prices substantially in excess of 
those currently prevailing to warrant 
development. 

Fore ign Supply 

Mexico appears to offer an opportunity 
for a secure, accessible, alternative 
source of manganese ore for the United 
States. 

There is an accelerating trend to con- 
vert manganese ore to manganese ferro- 
alloys by the ore-producing countries 
at the expense of production capacity in 
the United States and other consuming 
nations. 

PLATINUM-GROUP METALS 

Substitution 

Automotive emission control cata- 
lysts . - The development of a base metal 
catalyst with suitable efficiency and 
durability would constitute an unforesee- 
able breakthrough. 

Petroleum refining catalysts , - Substi- 
tutes such as molybdenum reduce process 
efficiency. 

Chemical processing cataly sts. - A low- 
er cost cobalt oxide alternative is 
available for nitric acid production, 
but certain performance aspects are 
inferior. 

Electrical and electronic . - Electronic 
switching systems, printed circuits, and 
metals such as gold, silver, and tin- 
lead alloys offer alternatives in many 
applications . 



Jewelry . - Gold and silver could read- 
ily substitute for platinum. 

Dental and medical . - Many applications 
now using palladium could revert to the 
traditional material, gold, albeit at 
much higher cost. 

Recycling 

The combination of low concentrations 
of precious metals and difficulties in 
converter collection presents technical 
and logistical challenges to automotive 
catalyst reclamation. 

Platinum petroleum refining and chemi- 
cal processing catalysts are highly 
recyclable. 

Very low metal losses are experienced 
in glass handling and forming equipment; 
worn parts are recycled on a toll-refined 
basis. 

Regulations 

A relaxation of auto emission standards 
or a moratorium on the use of catalytic 
converters could accomplish considerable 
conservation of platinum-group metals in 
a short time, but such action would com- 
promise environmental quality. 

Domestic Supply 

At assumed capacities, production from 
U.S. platinum deposits would be capable 
of satisfying less than 15 pet of annual 
domestic requirements. 

Foreign Supply 

Nearly all of the world's platinum- 
group metal reserves occur in the Repub- 
lic of South Africa and the U.S.S.R. 



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Portcullis Press, 1979, pp. 82-89. 

76. Anstett, T. F., D. I. Bleiwas, and 
C. Sheng-Fogg. Platinum Availability — 
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77. Loebenstein, J. R. Platinum-Group 
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file, 1983, 20 pp. 



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